Undertale/Characters

Everything About Fiction You Never Wanted to Know.


TOMATO SURPRISE WARNING:

This page contains one or more of the major spoilers known as Tomato Surprises. Knowing these in advance may negate the intended effect of the work.


Characters from Undertale include:

Main Characters

The Human

It's you!

A human child who fell into the Underground. They are the character the player controls during the game. In the Pacifist route, they are revealed to be named "Frisk".

Tropes exhibited by this character include:
  • Ambiguous Gender: The characters isn't given a gender, and the neutral pronoun "them" is used to refer to them.
  • Ambiguously Bi: Despite not having a canonical gender, they unashamedly flirt with male, female and gender-neutral monsters.
  • Ambiguously Brown/Amazing Technicolor Person: Their sprite has the same kind of "race ambiguous yellow" used by The Simpsons and Andrew Hussie's self-insert.
  • Anything That Moves: Regardless of whatever the player's gender is, they're allowed to flirt with many characters and monsters of any gender, even sentient jello molds and airplanes.
  • Ax Crazy: Boy howdy is them, in the Genocide route. But that's to be expected when your endgame is to kill absolutely everybody.
  • Badass Pacifist: If you choose to play that way. Every challenge in the game can be passed without having to hurt anyone, even if it comes close to ending the world itself at times.
  • Blood on These Hands: A variant: in a Genocide run, Papyrus specifically states that "your hands are always covered in dusty powder", which is what monsters turn into when they're killed.
  • Bunny Ears Lawyer: If you plan not to resort to violence, some of the things you'd need to do to spare monsters can come across as bizarre or maybe even border on Violation of Common Sense if taken out of context. Getting a sentient airplane to spare you by moving towards it isn't even the craziest thing you can do.
  • Casanova Wannabe: If the player so chooses, they can hit on most of the major characters and several ordinary random encounters. Never works out, though it's good for a laugh.
  • Cloudcuckoolander: It's very downplayed, but the fact that saving at save points reveal how the child seems to see the weirdness they encounter as signs of encouragement implies this.
  • The Comically Serious: They never change that overwhelmingly neutral expression of theirs, no matter how wacky, horrific or tear-jerking a given situation might be.
  • Cowardly Lion: Doesn't happen often, but there are moments where the dialogue box (during any non-Genocide run playthrough) implies that they might be scared of having to face certain monsters in battle, like Undyne, Muffet, Final Froggit, Mettaton and Asgore, but soldiers through facing them anyway.
  • Determinator: They doesn't give up on befriending every creatures, even when they're actively trying to murder them nor they stop in steadily depopulating the Underworld in the Genocide route. The Arc Words "determination" describe the Human's whole journey, which is about sheer, undying determination.
  • Dirty Kid: Played for Laughs, as it's possible to flirt with just about anyone.
  • Even Bad Men Love Their Mamas: Potentially, if you end a Genocide run by sparing Toriel. They'll gleefully slaughter their way through the Ruins, but can't bring themselves to harm her after she took care of them.
  • Face Heel Turn: It's possible to pull a Genocide run after completing a True Pacifist run. Given the revelations about the child's character from either route, however, it may not be done entirely willingly...
  • Fragile Speedster: During a Pacifist run, you'd be playing this part, as not getting any EXP means your maximum hit points remain 20. And while getting more powerful armors helps avert the 'fragile' part to a certain degree, you'll still need to have some skill at dodging attacks to survive most monster encounters.
  • Friend to All Living Things: In the Pacifist route, their goal is to befriend everyone, even those who on the surface appear to be irredeemable.
  • Good Is Not Nice: Although devoted to not killing a single monster, they isn't necessarily nice to others.
  • Guile Hero: A less violent protagonist ends up as this trope, taking advantage of the enemy's mindset to end fights without bloodshed.
  • Hidden Depths: Flowey heavily suspects and verbally speculates that the child desires a happy ending above all else. He also implies that the reason the child went to Mt. Ebott before falling into the Underground was to commit suicide.
  • Hope Bringer: Becomes an unwavering beacon of hope that everybody in the underground looks to during the Pacifist route.
  • Humanoid Abomination: Whatever the protagonist was before entering the underground, they're clearly not entirely human by the end of a Genocide run.
  • Implacable Man: The human child is full of determination. In the Genocide run, nothing is able to impede their rampage. Even if they are killed, they'll just come back from a checkpoint and try again.
  • Insert Player Name Here: You are supposed to name them in the beginning. Even then, the characters never call them for said name, instead calling them "human" or "kid". Subverted in that they isn't who you are really naming. They have an actual name, "Frisk". You are really naming the Fallen Child, the first human who fell in the Underground.
  • Jerk with a Heart of Gold: Can turn out as this, depending on how things progress.
  • Karmic Death: On the Genocide path, Papyrus offers to spare you in hopes that you'll turn good, but you kill him anyway in one hit while his guard is down. Much later during the Final Boss, if you accept their offer to spare you, the child will be hit with an unavoidable One-Hit Kill.
  • Kid Hero: While the child's age is never specified, they are just that — a child — and one who braves underground caverns full of monsters while armed with a stick.
  • Kleptomaniac Hero:
    • During a Genocide run, the Buy and Sell options in empty stores are changed to Take and Steal: the former lets you help yourself to the store's inventory for free, while the latter lets you empty out their registers at your leisure, although the latter option only gives any noticeable amounts of cash in Snowdin (presumably because it's the shop that had the least amount of time to evacuate, whereas Bratty and Catty operated out of a literal back alley over three quarters through the game).
    • Even during a Pacifist run, you still have the option of stealing three extra pieces of candy from the bowl despite being clearly told to only take one.
  • Lightning Bruiser: You become one in the Genocide route, as you'll be able to kill most monsters (including bosses) in one blow, easily survive damage thanks to having high HP and Defense, and you get to stay as fast as you'd normally be. The Genocide battles with Undyne and the final boss, however, can and are very likely to be challenging depite said powers.
  • Magnetic Hero: You can befriend every boss in the game.
  • Martial Pacifist:
    • While sparing monsters is the encouraged option, the child is more than capable of fighting back if pressed. Mettaton and Asgore are two crowning examples, the former being a Killer Robot and the latter being the king of all monsters. Even after these fights, they can elect to spare them, and they acknowledge that the child's unwillingness to kill has no effect on their overall strength, neither of body nor of character.
    • Even on a True Pacifist run, the child will need to fight the king. And they will win.
  • Muggles Do It Better: Because humans are physical, not magical (like monsters), their use of physical force is far stronger than any monster's, as evidenced by a Genocide or high-casualty Neutral run. However, this means that humans are vulnerable to magic (hostile or benign) that monsters are generally immune to.
  • Oedipus Complex: The child can flirt with the old goat lady after calling her mom.
  • Omnicidal Neutral: It's possible to a get a "kill everyone" ending without triggering the Genocide ending.
  • Pacifist: One posible way to interpret the character.
    • Technical Pacifist: The player can play the game in such a way that they doesn't kill any characters, but still battles and is a jerk to them.
  • Person of Mass Destruction: In the Genocide route, they murder their way through the underground.
  • Plot Allergy: To Temmies. This is unfortunate because they also like to pet humans, and without the allergy, they'd be completely harmless.
  • The Power of Friendship: In a Pacifist run, this is the only weapon they need!
  • Power of Love: They can be so good at this power that it even leads to Flowey surrendering to them, eventually.
  • Thou Shalt Not Kill: Naturally possible, the ability to play this completely straight in an RPG is one of the selling points of the game. Doing so is even necessary for the Golden Ending.
  • Tomato in the Mirror: One of the main reveals of the game is that the character you are playing with isn't the same person you named in the beginning. Many players get flabbergasted after this, specially those who used their own name.
  • Transformation of the Possessed: While it's not evident by looking at the sprite, their appearance is implied to become disfigured over the course of a Genocide run due to their murderous desire. Asgore won't even recognize them as human by the time they reach his lair.
  • Vague Age: They are never given an age and only ever described as a child. This means they could be anywhere between five and twelve years old. This is probably done for the same reasons as Ambiguous Gender. A large amount of the fandom seems to assume they are 8, however.
  • Villain Protagonist: If you choose the Genocide route. They go out of their way to kill every monster they can and are clearly satisfied when there are no monsters left in the area.
  • The Voiceless: They can speak, and you are allowed to make dialogue choices for them occasionally, but nothing they say is ever actually written out on screen.
  • Wholesome Crossdresser: Whether you imagine them as a boy or girl or nonbinary, in any case, they have no problem wearing ribbons, tutus, or manly bandannas with abs printed on them. Considering those things (somehow) raise your Defense, it's probably just for the sake of practicality.
  • Would Hurt a Child: In the Genocide route, they tries to attack Monster Kid for "being in my way".

Flowey

Howdy!

Someone ought to teach you how things work around here! I guess little old me will have to do.

In this world... It's KILL or BE killed.

The first character that the player meets when starting a new game. A friendly little flower who introduces you to the mechanics of the game. Though its advice ends up appearing a bit odd and misleading... because it is. It quickly turns out that Flowey is a sociopathic creature who wishes to make the player squirm and suffer, when not wishing to see the player inflict as much suffering as possible to the monsters in the underground.

Flowey provides examples of the following tropes:
  • Aesop Amnesia: Flowey ends up nearly orchestrating his own demise, and later calls out the player for preventing the scheme that would kill him from going through. Specifically, near the end of a Genocide run, Flowey finally realizes that "kill or be killed" means not even he is safe from you. Despite this, if you bail out, reset and complete a Neutral run, he will complain about how you screwed up their chance at true victory, even if you got to the point where he was mercilessly slaughtered and reset before the final decision. You'd think he'd be grateful that you spared his life.
  • Alas, Poor Villain: After defeating Flowey, the player can choose to spare him. Flowey will ask why the player would be so forgiving, after what he tried to do to them. Flowey struggles to understand this act of kindness and becomes saddened by it.
  • Already Done for You: In the Genocide route, one switch in Snowdin is pressed down by vines, indicating Flowey solved it before you arrived. Several future puzzles are already solved as well, but this is the only one definitely solved by him.
  • And I Must Scream: Flowey is a flower, thus it is neither human nor monster, which apparently makes it impossible for Flowey to feel any love whatsoever. Despite this, at some point, Flowey wanted to be able to experience love, but he simply can't, since he's trapped as a souless flower.
  • Bad Liar: He tries to come off as friendly and helpful, but his smug, insincere tone and short temper means that he's not particularly convincing as far as the audience is concerned. It's a different story for the characters... some are taken in by his act. Others, not so much.
  • Big Bad: Except in the Genocide route, where YOU are the big bad.
  • Book Ends: Flowey is both the first opponent you face in Undertale AND the last. In all routes.
  • Big Bad Wannabe: On a Genocide run. He believes that the player is willing to cooperate with him, but they're perfectly willing to kill Flowey. Flowey ends up trying to save his own skin, which leads to him becoming the final fatality of the Genocide run.
  • Break Them by Talking: Flowey really enjoys attempting to do this to you. At the end of the Ruins, for example, he'll give you a piece of his mind which varies depending on your actions up until that point. For instance, if you're in the clear for a Pacifist run and didn't kill anything without reloading to fix it, he'll question you on how long you can keep it up.
  • Cannibalism Superpower: Powers up to Omega Flowey after he absorbs the human souls and gains powers based on each of them.
  • Cruel and Unusual Death: On the worst ending, Flowey attempts to beg for mercy, only to be utterly mutilated and cut in half.
  • Cutscene Boss: If you've already completed a Pacifist run but fail to achieve True Pacifist the second time around, Flowey just plain skips the fight, already knowing how it ends. On the flip side, if you finish the Genocide route, the player doesn't even get a prompt to fight Flowey before he's defeated.
  • Defiant to the End: If you choose to kill him in the Neutral run, he gives one last evil grin and proclaims "I knew you had it in you!".
  • Devil in Plain Sight: He abandons his friendly facade almost immediately after you meet him.
  • Dirty Coward: Flowey is confident that the player will do little that can actually harm him, but when he finds someone who is willing and able to hurt him, his entire persona crumbles. He's ultimately revealed to be this toward the end of a Genocide run. He's not afraid of the human child since he seems to know that being killed will never have any permanent effects, and that he can still try to manipulate both of you toward his own ends. Once face-to-face with that child after they've killed most of the Underground, however, he crumbles when he realizes he's dealing with an unrepentant murderer who'd happily kill him for sheer amusement. Whereas in other playthroughs, Flowey has little problems fucking around with you, after this point, he's entirely devoted to saving his own neck, right down to pitifully and tearfully begging for his life.
  • The Dragon: Somewhat becomes this to you in the Genocide run, completing puzzles for you and making your playthrough quicker. He stops being your dragon when he figures you'll be out to kill him as well.
  • Eldritch Abomination: Flowey's boss form.
  • Establishing Character Moment: He is the very first character we meet, and seems friendly and helpful enough... but evade his "friendliness pellets" enough times (or be dumb enough to run into them) and he quickly show his true, cruel colors.
  • Even Evil Has Standards: In the Genocide route, the player becomes so twisted that even Flowey feels disturbed by them.
  • Evil Cannot Comprehend Good: Having MERCY on him after his battle completely befuddles him.
  • Evil Is Petty: It really doesn't help his plans any to mock and insult you constantly. He's just kind of a dick like that.
  • The Fake Cutie: He's an adorable, talking flower who introduces himself as supposedly your best friend, but that charade doesn't even last a minute.
  • Faking the Dead: If you kill him at the end of a Neutral run and then restart, he is absent from most of his scripted encounters. However, he still stalks you as before, and he'll fully reveal himself if you get another Neutral ending just to taunt you, saying that he comes back whenever you reset. All killing Flowey does is prevent him from giving you the hint for the True Pacifist route (though it's still achievable).
  • False Friend: To you, obviously, but also to Papyrus, who speaks of him fondly in phone calls. He manages to manipulate Papyrus into convincing Undyne to request the Protagonist to give Alphys the date invitation, and bringing everyone to Asgore's castle in the True Ending route.
  • Faux Affably Evil: AND HOW.
  • Final Boss: Flowey is one of three or so bosses the player can fight at the end of a route. Specifically, he's the Final Boss of the Neutral route. He must be fought at least once to open up the True Final Boss for True Pacifist, and in the Genocide run, he is a Cutscene Boss.
  • Finger Gun: During his boss fight, one of his possible attacks is conjuring hands that are performing the finger gun pose. Which then launch the fingers as projectiles. Did we mention the fingers also have flower faces at the fingertips?
  • Fluffy the Terrible
  • Formerly Walking Spoiler: Due to Late Arrival Spoiler and Pop Cultural Osmosis, Flowey's malevolence, which is supposed to be a surprise for the players, has become very well known. Note that a good chunk of his section is still very well covered in spoiler tags.
  • The Fourth Wall Will Not Protect You: There's no hiding what you did from Flowey. Not even if you reset. Did you kill Toriel, then reset, do her battle again, and spare her? Flowey's speech at the end of the Ruins makes it very clear he knows. And that's just one of the more blatant examples of this trope.
  • Giant Space Flea From Nowhere: At the end of a Neutral run, Flowey takes all the SOULs from Asgore after you defeat him and closes your game. When you restart, you have to fight his boss form.
  • Giggling Villain: Even though Flowey does a full Evil Laugh quite often, he will also occasionally just chuckle.
  • Go Out with a Smile: He sports a demented grin if you decide to kill him in the Neutral route.
  • Hypocrite:
    • If you dodge his "friendliness pellets" at the start of the game, he berates you for toying with him... which is exactly what he was doing to you mere seconds ago.
    • During the finale of the Genocide route, Flowey performs his Take That, Audience! to people who watch the Genocide route instead of playing it, calling them "sickos" and "pathetic", which is rich when not 5 minutes later, once he realizes that his kill or be killed philosophy includes himself, he cowers in fear of you and runs off and tries to hide behind Asgore, the man he admitted to killing time and time again because he was bored. What makes this worse is that earlier he says he doesn't want anyone to pity him, but right before you kill him, he cries begging you to, of all things, pity him and spare his life... it doesn't work sadly.
  • Jerkass: To put it mildly. His Establishing Character Moment alone has him attempting to exploit the player's naivety, to try and convince them to walk straight into his attacks.
  • Killer Rabbit: In Undertale, you meet all kinds of monsters, from skeletons to fish knights. And yet the most utterly depraved of them all... is a cute smiling flower.
  • Manipulative Bastard: He's been talking to Papyrus for a while, pretending to be his friend {{spoiler|so that he can exploit his naivety near the end of the True Pacifist run. He also attempts to do this with the player after a Neutral run, where he suddenly seems to have a change of heart and gives you real advice towards getting the True Pacifist ending. Both of these are plots that further his true goal.
  • Nightmare Face: He has an assortment of those. Just [dead link] observe. He is also fond of morphing his face to imitate other monsters. All of those are combined and exploited in his boss fight with his Omega form having a particularly deranged one.
  • No Final Boss for You: Played with, in that it's not due to a player missing something or playing poorly. If you've already done a run where you've beaten him and you haven't done a True Reset or Genocide run since, and you get to him again in a Neutral run, he decides to not fight you after you kill Asgore since he knows you'll just beat him again.
  • Not So Different: The player and Flowey, most notably if you decide to go through with doing a Genocide run after completing the True Pacifist route. Flowey will later on tell you that this is also how he felt; Flowey tried to be a genuinely nice flower, helping everyone, until he got bored of it and decided to be mean, started killing people, just to see what happened. Which is exactly what you're doing.
  • Not-So-Harmless Villain: At the beginning of the game, while he does cause harm, it's not obvious that he's the true Big Bad. After all, who would expect the flower with a god complex?
  • Not-So-Imaginary Friend: To Papyrus. Sans and Undyne don't believe he's real despite Papyrus insisting otherwise.
  • Omnicidal Maniac: Flowey wants to destroy EVERYONE, humans and monsters alike.
  • Post-Final Boss: On the Genocide run, the game basically ends with a brutal final boss fight. After that, the player deals with Flowey in a cutscene with no gameplay involved.
  • Puppeteer Parasite: Often portrayed as one of these in fanworks.
  • Reluctant Psycho: His monologue in the Genocide run brings up that he's genuinely upset over his inability to feel love and compassion along with the ensuing insanity, but doesn't think about a better life than toying with the people of the Underground along with his new human "playmate".
  • The Reveal: Flowey is actually Asriel's consciousness, devoid of actual emotions, trapped inside a flower.
  • Rewarded as a Traitor Deserves: In the Genocide run. At the end, once he realizes that the sociopathic child has no qualms about killing him, Flowey tries to warn King Asgore. When the child knocks Asgore away, Flowey attacks him in order to prove his loyalty and then outright pleading for his life, but is brutally hacked to pieces by the child.
  • Save Scumming: A battle tactic as Photoshop Flowey. He'll save the game before launching an attack, and then load if the player dodges it.
  • Schmuck Bait: After completing a True Pacifist run, Flowey says that now that everyone's happy, you could do a hard reset of your save file, destroying everything you've achieved in the process and resetting everyone's happiness. And instead try to do things differently... Just to see what happens. Which is exactly how Flowey turned out to be the way he is.
  • Series Mascot: His form is on the official site and the first page of the manual.
  • Slasher Smile: When he's in a particularly evil mood, he'll break out a toothy, horrific grin.
  • Smug Smiler: He keeps his grin even as he taunts, insults and tries to kill you. It's enough to make you want to reach through the screen and punch him in his stupid, grinning face.
  • Smug Snake: He's condescending, often refers to the human child and their friends as "idiots", and is overall an unrepentant, sociopathic Jerkass.
  • The Social Darwinist: Flowey's motto, which he never misses an opportunity to inform the child, is "Kill or be killed".
  • The Sociopath: His defining feature. He cares about no one but himself, exemplified by his philosophy of "kill or be killed". His monologue in the Genocide run reflects a more sympathetic portrayal of The Sociopath than most. Flowey is legitimately upset at his Lack of Empathy, but years of living without the capacity for love have driven him to his sociopathic nature by the beginning of the game.
  • The Soulless: A being with Determination and memories, but no SOUL and no compassion.
  • Stalker with a Crush/Stalker Without a Crush: At some points of the game, backtracking will reveal that Flowey was following the player.
  • Stealth Expert: Flowey can be seen snooping at the child from the entrance of some rooms if you walk forth and turn back. Throughout the game, he is aware of everything you do.
  • Take That, Audience!: In a rather meta sense in a Genocide run. Besides his typical You Bastard moments, he leans on the fourth wall and essentially calls out anyone who watches a livestream or video of the Genocide run because they want to see the carnage, but lack the stomach to do it themselves.
  • Teleport Spam: Basically how he gets around throughout the game.
  • Treacherous Advisor: The manual sets him up as an ally, and he's the first character the player meets, but it doesn't take long for him to reveal that he does not have your best interests in mind. Instead, he's only out for himself.
  • Unwinnable by Design: Exploited. His favorite attack pattern is an undodgeable ring of bullets slowly closing in on your SOUL. Usually after he's already reduced you to 1 HP through other means. Fortunately, fate tends to conspire to keep him from actually finishing you off.
  • Verbal Backspace: Flowey has done this twice:
    • If you dodge his "friendliness pellets" twice, he orders you to run into his bullets already, then glances at his speech bubble and corrects himself.
    • In the Kickstarter video, he says that you can "murder" monsters before hastily rewording it to "fight".
  • Vile Villain, Saccharine Show: Flowey is an emotionless murderer in an otherwise quirky and beautiful world, and the game makes no effort to hide it. Flowey himself is revealed as completely chaotic right from the get-go.
  • Villainous Friendship: During a Genocide run. Flowey is much less condescending and much more genuinely kind in this route, treating the human child like an old friend, which may not be far from the truth. Unfortunately, this comes back to haunt him when he realizes just how horrible the child really is...
  • Who Wants to Live Forever?: Due to his resetting abilities, Flowey has existed for such a long time that his interaction with other monsters has become so predictable and boring that he wondered what it'd be like to do terrible things instead. He says during the genocide route that he despises his seemingly never-ending existence.
  • Woobie, Destroyer of Worlds: Flowey's omnicidal tendencies developed because as a soulless flower, he is incapable of feeling love, even though he wants to.
  • You Will Not Evade Me: His favorite attack is surrounding you with pellets you can't easily evade. When he's got the drop on someone, he'll close a circle of pellets around them.

Toriel

I am Toriel, caretaker of the Ruins... I pass through this place every day to see if anyone has fallen down.

A friendly female monster who guides the player throughout the Tutorial Level. She insists on helping the player a great deal, perhaps more than is necessary (though the player eventually finds out why she's so overprotective). She used to be the queen of the Underworld, until the death of her children and her husband Asgore's decision of kill every human who fell in the Underworld compelled her to abandon him and take refuge in the Ruins.

Tropes exhibited by this character include:
  • Action Girl: It's important to remember that beneath her gentle demeanor is a powerful fire mage.
  • Actually Pretty Funny: Near the end of hard mode, Annoying Dog tells her that the hard mode's continuation would be "hard". Given her love for puns, she's very close to bursting out laughing.
  • Adorkable: Her love of terrible puns and "embarrassing and overprotective but lovable mom" vibe places her safely into this territory.
  • Badass Adorable: Absolutely huggable and a powerful magician who will completely wreck you if she doesn't hold back.
  • Barefoot Cartoon Animal: Wears a robe, but neither shoes nor socks, unlike most of the other monsters we meet. Yet she has a sock drawer in her room. Scandalous indeed!
  • Beware the Nice Ones: Toriel is powerful, and will give you a taste of it if you decide to ignore her warnings.
  • Boss Battle: The first one in the game, if you don't count Mini Boss Napstablook. You must defeat her in order to leave the Ruins.
  • Comically Missing the Point: According to Gerson, Toriel once wore a light blue dress with a floral pattern on it and people kept telling her that she had a nice muu-muu. Toriel mistook the compliments as her being called a cow and never wore it again, although she can be seen wearing it once more in the Golden Ending.
  • Cute Little Fangs: Has a very prominent and very adorable pair whenever shown in the dialog box.
  • Death Glare: Toriel can be surprisingly intimidating with her eyes, as the first Froggit can attest.
  • Does Not Like Shoes
  • Do Not Call Me "Paul": She kindly reminds a character to not call her by her ex-husband's surname, which is also likely her wish of not wanting to be associated with him. She also gets upset at her ex-husband calling her "Tori".
  • Evil Laugh: Toriel has one if you fake sparing her, then killing her... she'll let out a twistedly approving and heartbroken "eh heh heh", remarking that you'll survive just fine in the brutal world of monsters despite her misgivings.
  • The Farmer and the Viper: Toriel rescues you from Flowey, guides you through the Ruins, and give you a place to stay. If you don't spare her, then this trope is in effect.
  • Go Through Me: This is part of her boss battle of the Ruins, hoping to encourage you to go back to bed and take a nap. No matter what happens, whether she lives or dies, she doesn't end up happy.
  • Heroic Sacrifice: Is willing to die if you prove yourself strong enough to leave the Ruins, and is befuddled if you insist on sparing her until she eventually lets you go. Subverted if you're on a Genocide run, and she realizes you are a (figurative) monster.
  • Hopeless Boss Fight: Except that she doesn't actually want to kill you.
  • Intergenerational Friendship: With Sans, as they both enjoy bad jokes.
  • I Want My Beloved to Be Happy: She allows the child to leave the Ruins because she knows they would be unhappy growing up in their confines, without peers or friends.
  • King in the Mountain: The title of Asgore's theme "Bergentrückung" can also refer to someone that leaves the world behind to 'disappear' into the mountains, either willingly or by accident. It often is a king, but doesn't have to be. Ironically, the title fits Toriel better than him, since she fled society to isolate herself in the Ruins.
  • Leitmotif: "Heartache".
  • Memetic Sex Goddess: Confusingly enough, considering that she is a several-thousand-year-old anthropomorphic goat. But apparently that's the appeal. Humorously implied to be an in-universe case, as Undyne says "Thats gotts hurt" after learning she is Asgore's ex.
  • Mother Goat
  • My Beloved Smother: She solves the first "puzzle" in the game for you, tells you the solution to the second, and literally holds your hand through the third. She also scares away early random encounters for you. And at two different points, you can't advance in the game unless you ignore her instructions to stay put while she does something important. It is all played in a very endearing light though.
  • Nice Job Breaking It, Hero: If you're on a Genocide route, then her helping you is what allows you to reach the rest of the Underground.
  • Nice Lady
  • Not So Stoic: In the Boss Battle against Toriel, she consistently acts cold and aloof, but will display a sudden expression of shock and horror if she accidentally kills you. Also, as you keep pressing the Spare button during a Pacifist run, she will start to look doubtful, tear up and give a sad smile while trying to convince you to either fight or go back upstairs. Then she'll hug you at the end while ordering you firmly not to come back.
  • OOC Is Serious Business: Toriel is kind and motherly, but the few times something breaks her cheerful demeanor, she is dead serious.
  • Personality Powers: Played with. She isn't hotheaded, impulsive or violent, the typical personality traits associated with Playing with Fire. She instead embodies the concept of an enduring, nurturing flame... light, life, and warmth rather than chaos and destruction. The fire in the fireplace at Toriel's exemplifies this; the fire is warming, but not dangerous... the narration notes the child can even stick their hand in without getting hurt.
  • Punny Name: Her name is a pun in "Tutorial".
  • Red Eyes, Take Warning: Averted, for the most part. While she does have red eyes, she's not evil in any term. Though she's a very competent pyromancer and able to kick ass when needed.
  • Ridiculously Cute Critter: A very, very adorable anthropomorphic goat. Arguably, she's an Irish Púca.
  • Sacrificial Lamb: Depending on the route the player takes.
  • Secret Test of Character: Her boss fight is both a straight and meta example. She says "Prove to me you are strong enough to survive" as she blocks your way, expecting you to either back down or kill her, and her reaction to being slain normally implies she's alright with that outcome. It is also possible to Take a Third Option and spare her, but the game does not make this immediately obvious (especially since using Talk doesn't work) and seems to subtly test whether players are committed to choosing Spare over and over again until she backs down. The game implies, both subtly and not-so-subtly, that the first choice you make reveals the real nature of the player, and Flowey outright mocks you if you kill her then immediately reset. This includes trying to beat Toriel into submission (which traps the player into accidentally killing her), since you're still trying to use violence to get your way.
  • The Social Darwinist: Toriel believes it's "kill or be killed" in the Underground, which is part of why she's so protective. If you repeatedly "SPARE" her in battle, she eventually screams, "What are you doing? Attack or run away!". Persist, and you can prove it wrong. For now. Downplayed because she doesn't WANT it to be that way which is why she tries to stop you from leaving
  • Stealth Pun: She's an anthropomorphic she-goat and acts as a substitute mother figure for the player. In other words, she's a literal nanny goat. Also, if you become close, you become like her 'kid'.
  • Stop Helping Me!: While well intentioned, her help can be a little hindering.
  • Suicide by Cop: Forces you into a fight to the death... and then holds back. It's more of a Secret Test of Character to prove to her that you're willing to do what it takes to survive.
  • Supreme Chef: Her butterscotch-cinnamon pie is one of the few items that recovers 100% of your health. Unfortunately, she cannot make it in Hard Mode (since she neglected to go shopping beforehand) and instead makes snail pie, which is itself a decent item, healing you up to one point less than full health.
  • Technical Pacifist: She is the first serious boss, and she will fight you, but if your HP drops to 2, her attacks will start avoiding you...
  • Threshold Guardians: Played extremely straight. Toriel literally stands in your way before the door that would lead you outside the Ruins and asks that you show her that you have the will to survive and move forward... whether by violence or pacifism.
  • Trademark Favorite Food: Toriel enjoys eating snails, and in the Hard Mode route, she makes the player a Snail Pie instead of the usual Butterscotch-Cinnamon one on account of having not bought any groceries beforehand.
  • Utility Magic: Her fire magic mostly isn't used for combat, just cooking.
  • Voice Grunting: Sounds similar to the soft bleating of a goat.
  • Wake Up Call Boss: Her blocking the exit from the Ruins seeks to teach you about the game's boss battles. First of all, her attacks are much harder to dodge and and the battle is much longer than any previous battle. But equally important, she's the first opponent where sparing requires more thought than just "try everything in the Act menu once", and the first battle where sparing takes significantly more turns (and effort) than fighting.
  • Walking Spoiler: Toriel is a lot more than the simple motherly old lady you first meet...
  • Well-Intentioned Extremist: Toriel at the end of the Ruins wants to protect the player by destroying their only escape.
  • Would Hurt a Child: Entirely willing to beat the protagonist within an inch of their life to stop them from venturing outside to find a way home. That said, she will adamantly refuse to kill you even if you're about to kill her... others will not be so caring.
  • You Can't Go Home Again: Invokes this if she's spared. No matter how much she wants for the Ruins to be "home" for the protagonist, she lets them leave, but not before asking them to not come back.

Sans

i'm actually supposed to be on watch for humans right now. but... y'know... i don't really care about capturing anybody.

A funny skeleton who loves puns and often pulls pranks. The player meets Sans after leaving the ruins. He lives in Snowdin Town with his brother, Papyrus. Near the end of the game, the player meets him again, regardless of which path is chosen. He will then judge the player's behaviour. If the player is on the Genocide route, he will fight you.

Tropes exhibited by this character include:
  • Adorkable: Nowhere near to his brother's extent, but it's there despite his laid-back, cool, controlled air... consider his quickness to dole out cheesy puns and apparent fondness for somewhat childish pranks, as well as the fact that according to Papyrus he's something of a sci-fi nerd.
  • all lowercase letters: Sans almost always uses entirely lowercase letters, both in his dialogue text and his handwriting (to the point that one can tell something is said in-character by him simply by the lack of capitalization). You can tell that he is being deadly serious about something whenever he stops doing it.
  • Annoying Younger Sibling: Inverted: as much as he loves his brother Papyrus, he still finds great delight in annoying the ever-loving daylights out of him.
  • Beleaguered Bureaucrat: He's implied to become this in the Neutral ending where Papyrus becomes king by process of elimination. For the most part, all that Papyrus seems to do is make everyone spaghetti and listen to their problems, but he remarks that Sans is actually working a lot on things he's not entirely clear on, and hard at that, and that life has generally improved in the Underground.
  • Beware the Nice Ones: If you don't, you're gonna have a bad time.
  • Big Brother Instinct: He completely adores his young brother Papyrus, and does everything to care and provide for him. He tries to get a similar relationship with the player. If the player kills Papyrus, he enters in Heroic BSOD and disappears from the game until the judgement.
  • Big Brother Worship: Sans makes it clear on many occasions how cool he genuinely finds Papyrus, for all he messes with him.
  • Big Fun: He is somewhat big boned, he is constantly telling jokes, and is well known and loved by a lot of characters.
  • Big Good: Sans ends up as this at the end of a Genocide run, when he's the final force of good that's powerful enough to stand up to Genocide player and their goal of world domination.
  • Big Guy, Little Guy: The worldly, wisecracking, all-lower-case little guy to Papyrus' innocent, boisterous, all-capitals big guy. Sans is ostensibly in charge, paying for their house and all, but Papyrus is the one who keeps him on the straight and narrow.
  • Brilliant but Lazy: Sans is a self-described lazy skeleton without a care in the world. However, he does have incredible power, and he's willing to show you if you take things too far. He is also implied to be scientifically adept, but he takes the comparatively easier jobs of sentry, comedian and hot-dog seller.
  • Celibate Hero: Sans is too lazy for a relationship, going by Word of God. The game somewhat supports this notion too; romance is definitely not the guy's priority. This doesn't stop him having Ship Tease with Toriel, however, and the rabbit monster at Grillby's seems to be into him. Keep in mind it is never stated he is asexual or aromantic just that he is too lazy to hold a relationship.
  • Chekhov's Gunman: He seems like a simple joker at first (though he can be a bit scary early on in the Genocide run), but as you find out later, he is the only reason you were able to make it as far as you did. In fact, he's been helping you all along... after all, what would a sentry from Snowdin be doing outside of his station, selling items that just so happen to help raise your health?
  • Cool Big Bro: For as much he enjoys messing with him, Sans' relationship with Papyrus is remarkably strong. He's laid-back, quick with a joke, and appears to be very popular with the town residents, yet he still considers his dorky brother the coolest person he knows. Played with in that despite Sans being by far the more traditionally cool of the two, he's still the one who admires Papyrus in this way while ostensibly playing a role more similar to an Annoying Younger Sibling.
  • Dem Bones: He's a talking skeleton who loves to eat and sleep.
  • Exposed to the Elements: Not nearly as much as his brother, but he's still wearing shorts and slippers in the snow.
  • Foolish Sibling, Responsible Sibling: The foolish one, what with his laziness, albeit he has traits of the responsible one (he seems to be the actual breadwinner, having multiple jobs).
  • Foil: To the Fallen Child. Both characters are almost perpetually smiling, but with Sans, it is used as a funny detail. With the Fallen Child, it's meant to make them seem creepy. This is even further if the Fallen Child as the narrator which would mean they are both Deadpan Snarker types with a love of puns.
  • Funetik Aksent: His "-ing" words usually end in an "-in'", he says "'em" instead of "them", and he occasionally strings words together like "forgeddaboudit" and "howzabout it". Since the game has no voice acting, fans typically interpret this as some variety of New York accent.
  • Good Is Not Soft: If the player has behaved like a Complete Monster throughout the game, Sans will use everything in his power to destroy you.
  • Hero Antagonist: If the player is on the Genocide route.
  • Heroic BSOD: If you kill Papyrus, regardless of how few others you kill, Sans completely disappears from the game until his judgement. He cares a lot about his brother.
  • Honor Before Reason: In a Genocide run, because he promised not to kill any humans, he only intervenes when it's clear you are about to destroy everything, and not at any other point, when he ought to have shot you at the very least after you kill Papyrus.
  • The Hyena: His Voice Grunting is a low-pitched chuckle. Hehehehehehe...
  • Japanese Pronouns: In the Japanese localization he uses "oira", a pronoun associated with country bumpkin and relaxed characters, very fitting for his easygoing self. The reveal of this trait caused an stir in the Japanese fandom (who expected him to use either "ore" or "boku"), which in a meta way also fitted his troll tendencies. It's implied to be a deliberate affectation on his side to make himself less threatening - on the "Lost Soul" sequence in the Pacifist final battle, he defaults to "ore".
  • Joke Character: Subverted in one of the most incredible ways possible.
  • Leitmotif: "Sans" and "Megalovania". Although the latter song isn't native to this game, it was composed by Toby Fox long before he made Undertale.
  • Losing Horns: When the Annoying Dog eats Papyrus' stash of bones and gets away, Sans peeks out of his room and plays a few mocking notes on a trombone.
  • Man of a Thousand Voices: In-Universe example. He does a pretty good Toriel impression, insofar as you can tell from the sound of text scrolling. According to Toriel, he also does a great Papyrus impression (Toriel is able to recognize Papyrus via his voice).
  • Meaningful Name: Sans is derived from Comic Sans, the font which his dialogue is in. Which is also a Pun; "Comic Sans" because his name is Sans and he likes to tell jokes. In a meta way, Comic Sans (the font) is a very popular font (to the point of overuse and use in very inappropriate contexts) that's hated by graphic designers and typography aficionados, as they see it as an "easy, lazy choice" by people who want to veer out of the default fonts in word processors and bring some "fun" to their texts; now compare that perception with Sans' personality.
  • Meta Guy: He seems to be aware enough of the Fourth Wall and that he is in a video game universe.
  • Mysterious Backer: Pops up here and there to provide you help in the form of advice, emotional support, affordable healing items and ambiguous threats.
  • Neutral No Longer: During a Genocide run, Sans tells himself that "I can no longer afford being lazy" and confronts the murderous player character near the end of the game. This is major, considering that if the player is on a Neutral route, yet killed his brother Papyrus, Sans does still let you past despite knowing the terrible thing(s) you've done. Thus it does take Sans A LOT before he gives up his laid back attitude and decides to interfere with the plot.
  • Obfuscating Stupidity: The more you know him, the more apparent it becomes that a good part of his goofiness is faked.
  • Older Than They Look: His age is extremely vague, but he's clearly an adult. Despite this, his overworld sprite is almost eye-to-eye with the player character's, and his presumably more-proportionate battle sprite is still squat enough to give the impression that he's a child.
  • Pungeon Master: The main purveyor of puns in the game. Sans enjoys harassing Papyrus with bad skeleton-related puns.
  • Red Oni, Blue Oni: The blue to Papyrus' red (blue clothing, calm personality).
  • Sad Clown: As the plot advances he is increasingly shown to be one. In the Genocide route, he explicitally spells it on his battle.
  • Sensitive Guy and Manly Man: The manly man to Papyrus' sensitive guy, being far less emotional and more traditionally masculine.
  • Sibling Team: Sans works with his brother Papyrus to capture any humans that come into Snowdin. Well, Sans doesn't work, per se, but he's always around to crack a joke while Papyrus fusses about.
  • Sibling Yin-Yang: As mentioned previously, although they do have some important similarities, he and Papyrus contrast each other in almost every way.
  • Skull for a Head
  • The Slacker: Sans takes laziness to an art form. At one point, he converts a guard booth into a makeshift shop to hawk food to passersby. As an impressed Papyrus notes, he's not doing his job by doing another job.
  • So Proud of You: To the Human during the judgment if you don't kill anyone.
  • The Spook: Apparently, he and his brother just sort of showed up in Snowdin one day. With Papyrus, it's less apparent, since he wears his heart on his shoulder, but Sans keeps most people at an arm's length, and it's never made explicitly clear just how much he knows about (or is involved in) any given plot point, though it's at least a fair bet to say "quite a lot".
  • Stepford Smiler: He is more than implied to be one, his brand of smiling being a clownish act. His smile rarely falters, even in the Genocide route. In his secret workshop, there is an album with a picture of him with some other people, and the description given of it is "Sans look really happy". Think about it for a second.
  • Teleportation: his ability to "take shortcuts" to virtually anywhere in the Underworld.
  • Tragic Dream: We don't know exactly why, but he really, really wants that machine in his secret room fixed. Sadly, Word of God has stated that this will never happen, and he's long given up even trying anymore.
  • Tranquil Fury: His main way to signal he is actually serious.
  • Trash of the Titans: His room turns out to have a literal trash storm in it.
  • Unexplained Accent: As mentioned above, he seems to have some variety of New Yorkian accent. Pretty weird coming from a guy who's spent his entire life underground among monsters who mostly lack readable accents, especially since his own brother doesn't even have one.
  • Walking Spoiler: There's quite a bit more to Sans than just the joke-loving skeleton you meet early on. Those avoiding spoilers take heed: even glancing at fanart of Sans will almost certainly give away something about his character.
  • What the Hell, Player?: If the player has been cruel throughout the game, Sans will probably call you out eventually.
  • Why Do You Keep Changing Jobs?: He seems to have a lot of jobs running out almost simultaneously, like two sentry points, an illegal hot dog stand and even a gig in MTT Resort.
  • You Bastard: If the player kills Papyrus on a Neutral run, they will get called out by Sans as a "DIRTY BROTHER KILLER".

Papyrus

NYEH HEH HEH!!

I WILL CAPTURE A HUMAN! THEN, I, THE GREAT PAPYRUS... WILL GET ALL THE THINGS I UTTERLY DESERVE!

Brother of Sans. Papyrus aspires to become a member of Asgore's royal guard, and receives training from royal guard commander Undyne, who recently gave him the order to capture the player by demand of the king. Fortunately for the player, he is too nice and eager of being friendly to actually succeed. He is a fan of puzzles and cooking.

Tropes exhibited by this character include:
  • Adorkable: Oh, so very much. He loves puzzles, wears armor that is actually just a costume he used in a party once (calling it his "battle body", according to Sans), collects action figures, has a racecar bed, and is looking for friends and respect. His "date" with you just cranks this Up to Eleven, as he has to rely on a manual to be able to know what to do.
  • Alas, Poor Yorick: He actually says this word for word, save for substituting his own name in, if you kill him in a Neutral run. His head lands on his hand, and he utters that line before his body turns to dust.
  • Animals Hate Him: One particular animal... the Annoying Dog, who seems to enjoy tormenting him for no obvious reason.
  • Annoying Laugh: He laughs "NYEH HEH HEH!!" constantly.
  • Annoying Younger Sibling: Inverted. Sans is amused at Papyrus being so Adorkable, and Papyrus has this reaction towards his older brother being lazy.
  • Anti-Villain: Papyrus himself isn't really evil, he is only a "human hunting fanatic" because that is treated as okay in the Underground. Even then, he is still a Nice Guy to the human player.
  • Affably Evil: Not really evil. Depite being a "human gunting fanatic" hes mostly an Adorkable Nice Guy
  • Awesome Ego: Refers to himself as "The Great Papyrus" constantly.
  • Badass Adorable: He's easily one of the most endearing characters in the game (which is saying a lot), and his battle prowess is at least close to that of Undyne's, if not far greater. In fact, the only reason he's not already in the Royal Guard is he's just that sweet and lovable ... for how powerful he is, Undyne knows he could never hurt a fly.
  • Ballistic Bone: His main form of attack. He actually has a cardboard box in his room containing all the bones he used in his fight against you.
  • Bare Your Midriff: His "battle body" only covers up half of his top, and his other outfits also show off his lower spine. He's one of the taller characters in the game, so finding clothes that fit him would be a bother.
  • Big Brother Instinct: Although Toby suggested that Papyrus is the younger brother, he does try to take care of Sans and was the one who encouraged him to get a job. He states Sans is 'lucky to have such a cool guy taking care of him'.
  • Big Ego, Hidden Depths: Despite Papyrus's Small Name, Big Ego, he seldom comes across as having the typical arrogance or buried self-doubt that his type of character is usually portrayed with. He just seems to be very enthusiastic in how much he believes in himself. Also despite how klutzy he is, his enthusiasm is so potent that even Undyne decided to look past his goofiness to give him a shot at being a soldier. She even admits that he trains hard enough that he actually could be part of the Royal Guard based on his combat skill if he weren't so innocent as a person. He's also capable of being very sly, such as when he realizes that Undyne will put in the effort to befriend you if he makes it into a challenge. He also has some pretty witty Deadpan Snarker lines if you call him in certain rooms. He even mentions things that happen later in the game, such as "phones that can turn into jetpacks" and Mettaton's "eyes" (which he doesn't have at that point).
  • Big Guy, Little Guy: The loud and exuberant big guy to Sans' low-key laid-back little guy. He might be the one who looks after the house and Sans, but at the end of the day, Sans is the one who dotes on him.
  • Black Bead Eyes: While Sans has large eyesockets with eyelights for pupils, Papyrus instead has smaller eyesockets that resemble beady eyes (though he does sometimes get bug eyes for a comedic expression).
  • Blatant Lies: After his "special attack" is stolen by the Annoying Dog, he launches an "absolutely normal attack". Said attack is also his longest and most unique attack.
  • Boss Remix: His normal theme "Nyeh Heh Heh!" is replaced by "Bonetrousle" once the boss battle turns serious.
  • Chaste Hero: Unlike his brother, who apparently isn't dating anyone out of laziness, Papyrus seems open to the idea of having a romantic relationship, but clearly doesn't understand how they work at all.
  • Cool Loser: Even when he has absolutely no hope of ever becoming a part of the Royal Guard, he has an unrivaled friendliness that easily beats Toriel's.
  • Dem Bones
  • The Ditz: Papyrus' defining characteristic, besides his ego and friendliness, is how naive he acts. If you call him frequently throughout the game on his cellphone, it becomes apparent that he doesn't really know much about how the monster world works. That said, he isn't stupid.
  • Does Not Know His Own Strength: He thinks he's weak and resolves to work harder to make it into the Royal Guard. Undyne notes that while he's not the strongest monster by a long shot, he's definitely strong enough to be a soldier... it's his naïveté that's the problem. Nowhere is this more evident than in the "absolutely normal attack" he seems entirely disinterested in having to use after his special attack is stolen. Said "absolutely normal attack" is one of the toughest attacks in the game to avoid. That said, he averts this trope in one important way... he will never hit the player with lethal damage; he will always stop the attack at 1 HP and end the fight.
  • Dreamworks Face: His facial expression during his boss fight. While he is a Perpetual Smiler (a given due to him being a skeleton), his eyes during this fight turns it into this, implying an extreme sense of confidence in himself at this point in the game.
  • The Dutiful Son: Cooks and keeps the house in order while his brother lays about and does little. Granted, Sans is the family breadmaker and keeps their bills paid, but he clearly sucks at his job, and even Papyrus doesn't know where he's actually getting his money; given what we know, it's probably something underhanded.
  • Entertainingly Wrong: After getting his hands on a pirate flag, Papyrus comes to the conclusion that humans evolved from skeletons. Considering how little he knows about humans, it's as valid a conclusion for him to draw as any.
  • Exposed to the Elements: Seems completely comfortable wearing next to nothing in the icy weather of Snowdin. Again, possibly justified since he's a skeleton. Undyne even complains to him how he can stand the chill when she's freezing.
  • Extraverted Nerd: Maybe not a traditional example, but he is extremely extroverted and certainly a variety of nerdy.
  • Flexing Those Non-Biceps: Can be caught doing this a lot. A particularly funny example, considering they're literally non-existent in his case.
  • Foolish Sibling, Responsible Sibling: Manages to be both to Sans. When it comes to behavior and lifestyle, he is the responsible one. When it comes to intelligence and maturity, he is the foolish one.
  • Friendless Background: Other than Sans and Undyne, he doesn't have any other friends to begin with, and you can potentially become his friend after your "date" which is required for the Golden Ending.
  • Friendly Enemy: He's unrelentingly nice even when he's supposedly trying to capture you. When you do actually fight Papyrus, it even ends with him offering to become friends for real.
  • Gentle Giant: Undyne mentions that Papyrus is actually very strong, and that the only reason he's meek during battle is because he's too nice and doesn't actually want to hurt anyone. In an case of Gameplay and Story Integration, the game stats actually supports Undyne on this respect.
  • Glory Hound: A sympathetic example. At first, Papyrus wants nothing more than to capture a human and gain prestige, but he just wants to be recognized for all his efforts. He's also completely ineffectual, which helps.
  • Good Cannot Comprehend Evil: Papyrus's love for everyone he runs into, coupled with his naïvete, makes it difficult for him to grasp why certain people do bad things. This really doesn't go well for him if you take a Genocide run. Papyrus can't grasp why the Fallen Child is so bad and is sure that it would only take an understanding friend to make them a better person. Even if you kill him, he'll die assuring you that you can be a better person with just a bit of effort. No way can someone be evil enough to kill everyone in the Underground... Right?
  • Good Is Dumb: Papyrus is not actually that dumb, but he is very naive.
  • The Heart: Other than gloat about his greatness or making puzzles or undercooked spaghetti, what Papyrus does best is instilling hope in people (even murderous ones) just by being his own optimistic self.
  • Hero Antagonist: If the player is being merciless, he attempts to stop the massacre... with love and understanding. Papryus is so sympathetic that he may in fact be a bigger obstacle to completing a Genocide run than Undyne or even the final boss, since some players can't bring themselves to kill him.
  • Heterosexual Life Partners: Although he and Sans are brothers, their relationship also easily qualifies as this. See Sans' example above for more details.
  • Hot-Blooded: Comes with hanging around Undyne too long. Whatever he does, he does it either with one hundred percent effort, or not at all.
  • HP to One: It's impossible to get killed by Papyrus. An attack that would normally do so brings you to 1 HP instead, and the rest of his attack is halted so he can capture you.
  • I Just Want to Have Friends: The main reason he wants to capture a human and get into the Royal Guard is for others' friendship and respect. If you offer to be his friend instead, he'll agree without hesitating.
  • Incorruptible Pure Pureness: Never becomes bitter towards you, even as you kill him.
  • Ineffectual Sympathetic Villain: At first as a Punch Clock Villain. He tries so hard to become part of the Royal Guard, but he's too goofy and friendly to be taken seriously, not to mention his attempts to capture the human with puzzles and his completely ineffectual security measures. He gives up on it once befriended.
  • Insult Backfire: He is completely oblivious to any rudeness directed his way. He might think you're insulting yourself, or thank you for your honesty, or misconstrue your statement into something complimentary about him.
  • It's All About Me: Falls firmly into this. He even feels like the human child's entire journey was to get him into the Royal Guard. Still, his friendliness, outgoing nature and downright earnest support keeps this from being the slightest bit antagonistic.
  • Joke Character: Downplayed. Your fight with him isn't that easy, depending on the route. But it is definitely a light-hearted battle. Papyrus also is far from weak; he's likely taking it easy on you because he dislikes fighting.
  • Keet: Papyrus is always extremely enthusiastic about everything he does and lightens up the mood of pretty much any scene he is in.
  • Kindhearted Simpleton: Easily the ditziest character in the game, but also among the kindest, even in a world overflowing with nice people.
  • The Knights Who Say Squee: He wants to be accepted into the Royal Guard so badly, in no small part because of how much he worships Undyne.
  • Large Ham: Highly boastful, with No Indoor Voice.
  • Leitmotif: "Nyeh Heh Heh!" and its remix "Bonetrousle".
  • Lethal Chef: Undyne motivated him take up cooking as a hobby in the first place, and as a result, he takes a lot from her. Sans notes to the player that Papyrus' cooking actually has been slowly but steadily improving since he started, though that he also believes that Papyrus finally making a dish that is edible is still a far way off.
  • Living Emotional Crutch: His overly jovial, kind and optimistic personality is what still brings a genuine smile on his pessimistic brother's face. Papyrus' love for life motivates Sans to keep going on, and if you kill him, you wouldn't be welcome in the monsters' world anymore, to put it kindly.
  • Losing Your Head: Killing him causes his head to fall off. He's able to keep on talking even after his body has turned to dust, although his head will inevitably turn to dust as well a few seconds afterwards.
  • The Magnificent: He calls himself The Great Papyrus.
  • Man Child: We don't know how old he is exactly, but he's adult enough to be a sentry and have Undyne be willing to train him for the Royal Guard, yet still childish enough to believe in Santa and need a bedtime story to go to sleep.
  • Masculine Girl, Feminine Boy: The feminine boy to Undyne's masculine girl.
  • Meaningful Name Just like Sans, his name is derived from the font his dialogue is in. Papyrus also refers to a form of paper used in ancient Egypt; Bonetrousle, his theme, has a stereotypical Egyptian sound to it. In a meta way, Papyrus (the font) is usually derided by professional designers for being loud, obnoxious, and an perfect example of "trying too hard" to being exotic and special without actually being either, qualities that can also describe the character.
  • Mercy Mode: Lose to him enough times, and he'll just skip the fight to befriend you the next time you encounter him.
  • Minion with an F In Evil: He comes off as this while he's still trying to capture you.
  • Mysterious Past: While it's far less apparent in his case, both he and Sans have absolutely nothing about their past elaborated on outside of a few intentionally-dubious hints. In fact, there are even less hints given about Papyrus.
  • Nice Guy: Papyrus always sees the good in everyone, and bears no negative feelings to any creature, be they human or monster. Despite his aspiration to become a royal guard, in truth, he could hardly hurt a fly because of how nice he is, which is also why Undyne isn't granting him the position; Papyrus is powerful enough to be a royal guard, but he'd be too friendly to ever get his hands dirty.
  • Non-Lethal KO: Papyrus cannot actually kill you. If an attack of his would've done so, it'll just reduce your HP to 1, and he'll just imprison you in the easy-to-escape dog house.
  • Not-So-Harmless Villain: While not a villain, from your exit from the Ruins clear until the tail-end of Snowdin, Papyrus has been a complete non-issue. Not only unable to hurt you, but unwilling to try, at that; he's actually more nice than anything else. When he finally fights you, his attacks slide along the floor, being impossibly simple to avoid. Even his supposed deadly "blue attack" does nothing of worth... until you realize the "do not move" shade of blue was not the one used to describe his attack. Suddenly, you can no longer move freely... your SOUL has "gravity" to it. "Bonetrousle" kicks in. Game on.
  • Obfuscating Stupidity:
    • When he first meets the player, he states that he doesn't know what'll happen after the human is delivered to the capital. However, after sparing him in a Neutral or Pacifist run, he states that the king "wants to open the barrier with soul power" and soon after tries to beg Undyne not to destroy the human, indicating that he knows that the human will be killed for their SOUL.
    • When calling him in Alphys' lab, he'll gush about how Sans would love it. However, if he's called in front of Alphys' lab, when Sans is with him, he'll act like he doesn't know what a lab is, even mispronouncing it as "laboradory".
  • One-Note Cook: he only seems to prepare pasta, and seems very knowledgeable about it. Pity that he isn't a good chef to begin with...
  • OOC Is Serious Business: Despite being the definition of a Wide-Eyed Idealist, Papyrus is still able to recognize your wickedness during the Genocide route very shortly before your fight with him, as well as how truly dangerous you are. This is very important, as it makes his plea for you to lay down your weapon not an act of naiveté, but a display of actual, legitimate faith that you can change for the better.
  • Painting the Medium: In the Japanese translation of the game, his text reads in the traditional Japanese right-to-left manner rather than the left to-right everyone else uses.
  • Perpetual Smiler: Always grinning like a goofball. Though being a skeleton, that's kind of a given.
  • The Pollyanna: Never gives up hope, no matter what's thrown his way. You can literally murder him in cold blood, and he reacts by sincerely encouraging and promising you that you can be a better person if you just try hard enough, no bitterness in his words whatsoever.
  • Punch Clock Villain: As an aspiring member of the Royal Guard, he tries to fit the mold, but he's seen as such a good person that Undyne won't let him throw himself into such a dangerous position, even when she acknowledges his sheer strength and skill.
  • Pungeon Master: He has a more subtle undertone than Sans, even if he gets annoyed by the latter's more audacious ones.
  • Puppet King: A benign version, but if he becomes king in the Neutral ending, Sans ends up doing most of the actual work running the country.
  • Red Oni, Blue Oni: The red to Sans' blue (red armor, enthusiastic personality...).
  • Running Gag: The Annoying Dog stealing his bones, his obsession with spaghetti, his "STANDARDS!!!", and his hatred of puns.
  • Sensitive Guy and Manly Man: The sensitive guy to Sans' manly man, being far more emotional and less traditionally masculine.
  • Shameless Self Promoter: Rarely misses a chance to promote his own greatness.
  • Sheathe Your Sword: He attempts to bring the player back from the brink by refusing to fight them.
  • Sibling Team: With Sans.
  • Sibling Yin-Yang: As mentioned above, he and Sans seemingly differ in almost every possible way.
  • Skilled but Naive: Papyrus can effortlessly restrict the range of motion of the child's soul for extended periods of time, and manipulate the battle plane, two abilities that are otherwise virtually exclusive to the toughest boss in the game. The only thing keeping him from being a serious threat is his total unwillingness to kill and inexperience in fighting humans. The 'Skilled' part of this trope becomes more apparent when you consider how, again, it's impossible to die at his hands. He can, and will, straight-up stop the fight when you're down to one hit point; this sort of feat that would suggest that he can use his attacks with skill and precision that even Toriel lacks (and indeed only Asgore shares).
  • Skull for a Head
  • Spikes of Doom: He's fond of these as obstacles, according to various phone calls with him.
  • Stepford Smiler: If most of the monsters are killed, and Papyrus is left to rule the Kingdom of Monsters by process of elimination because Toriel, Undyne, Mettaton and Alphys are dead. He tries to maintain a cheerful disposition around the few survivors, especially around his newly hard-working brother, but confides to the player that being lonely and unable to raise anyone else's spirits is very difficult.
  • Stereotype Flip: He's vain, never wastes an opportunity to promote his own greatness, thinks your entire quest was for his sake alone... and is an unbelievably nice guy who cares for everyone everywhere.
  • Stock Video Game Puzzle: Papyrus is fond of creating these to trap humans. He's not very good at it: when he doesn't inadvertently reveal the solution right away, he instead fails to make sure that you can't just walk past the puzzle unhindered. The only time he actually makes even a remotely difficult puzzle is when he fiddles around with an existing one out of boredom to make it look more like his face.
  • Sudden Anatomy: Randomly gets huge buggy eyeballs during his more exaggerated expressions.
  • Technical Pacifist: Papyrus will fight you in order to capture you. But he wants to capture you, he DOESN'T want to kill you, which is why he will end the fight and put you in his shed if your HP drops to 1.
  • That One Puzzle: In-Universe, he defies this trope with his belief that all his puzzles should be fair, which is why he cancels his "Gauntlet of Deadly Terror", a timing puzzle that could easily kill the player character (although it's possible that he either forgot the password that activates the puzzle or more likely, doesn't actually want any harm to come to them, as shown in most tropes associated with him).
  • Theme Music Power-Up: His battle starts as joke as all of his attacks can be avoided by not moving, during which his overworld theme "Nyeh Heh Heh!" plays. Then he turns your soul blue, making it affected by gravity, then his real battle theme "Bonetrousle" starts to play.
  • Thou Shalt Not Kill: He won't kill you if your HP gets down low enough. Instead, he'll lock you in his garage with dog food and a dog bed and eventually call off the fight if you get captured three times. It's part of the reason why Undyne won't let him join the Royal Guard since he is "too sweet and innocent".
  • Too Good for This Sinful Earth: On the Genocide route. He's perfectly aware of what you've done and what you can/will do to him, but he spares you immediately nonetheless, with the belief that you still have the capability to become good.
  • Trademark Favorite Food: Spaghetti. He will let you know about this fact, many times. In the First Anniversary event, it was revealed by Word of God that his actual favorite food is "that oatmeal with the dinosaur eggs." He actually never eats the pasta he cooks, he just cooks it because he is convinced other people like it.
  • Undying Loyalty: Papyrus, provided you've spared and befriended him, will actively try to hinder Undyne's assault in the Waterfall. He's not very good at it.
  • Verbal Tic: "WOWIE!"
  • Voice Grunting: A weird chattering noise, likely meant to sound like a cartoonish bone rattle.
  • "Wake-Up Call" Boss: His battle. He is the first enemy who subvert the shooting mechanics, and goes for plataforming mechanics with his Blue attack.
  • Wide-Eyed Idealist: Undyne cites it as the reason she can't let him in the Royal Guard: he's strong enough, but he's simply too sweet and innocent to handle the position. Notably, he's the only enemy in the game that won't give you a game over if he defeats you in battle... he's specifically in it to capture you, and will just leave you in his shed, with only a basic fence to keep you there. Even in a Genocide run, he'll immediately offer to spare the child when they fight, believing they still have it in them to be a good person. If you take him up on it, he lets you move on without any more trouble... and even when killed, he'll have no regrets, and continue to say that he thinks you can change.
  • Workaholic: Implied, since he always seems busy and considers 7 hours of sleep a night to be a waste of time. He's also always punctual, answers his phone within two rings no matter what, and in one phone conversation, mentions that he'd never go on vacation after he and Undyne joke about it.
  • Would Hurt a Child: He has absolutely no qualms about beating the player character within a hit point of their life, even irritably lecturing them on how to fight if they aren't good enough at it for him, then dragging them off to throw them in a cage in his shed-turned-prison with a bowl full of dog food to eat after he's knocked them out. Sure, he won't go as far as to kill anyone, but he's surprisingly brutal.

Undyne

No, you know what? SCREW IT! WHY SHOULD I TELL THAT STORY WHEN YOU'RE ABOUT TO DIE!?!

Leader of the royal guard. She hunts the player in order to deliver their SOUL to the king.

Tropes exhibited by this character include:
  • Action Girl: She loves fighting and big swords. What else could she be?
  • Adorkable: It's downplayed, but it is there, most notably in how she genuinely believes that anime is real.
  • Ambidextrous Sprite: Her overworld sprite is mirrored and leaves a glaring mistake. When walking to the left, Undyne doesn't have her eyepatch on.
  • Anti-Heroine: Of the "actually heroic but still a jackass" variety.
  • The Apocalypse Brings Out the Best In People: During a Genocide run, she prevents you from murdering the Monster Kid by jumping in front of him and taking the blow you meant for him. Then she proceeds to fight until the bitter end, making her own determination.
  • Arc Villain: Of Waterfall, in the same way that Mettaton is the arc villain of Hotland. Throughout Waterfall, a fairly backstory-heavy level, you're constantly pursued by Undyne, who is intent on killing you, regardless of how you've acted up until this point. Her battle marks the point where you start making great strides towards returning to the surface. Undyne could also be viewed as this to Snowdin, since Papyrus is a total non-threat... it's wanting to please Undyne that drives him to fight you.
  • Armor Is Useless: Before a patch, she had negative defense in her boss fight, despite being covered in plate armor. During her un-armored rematch after the "date", she somehow had more defense. A later revision fixed this, though her heavy armor still doesn't help if you opt to kill her. Also, if you don't want to kill her, the armor proves detrimental; the key to beating her there involves getting her to chase you into Hotland, where she succumbs from exhaustion from the heat made worse by the armor.
  • Asskicking Equals Authority: Until you encounter Undyne, the only members of the Royal Guard you've seen are five silly dogs that can be gotten past by petting. When Undyne shows up, she makes it very clear that she's the leader of the guards for a reason. Depending on your actions in the Underground, she might decide that Toriel (who's hardly a push-over herself) is too soft-hearted to become Queen after Asgore's death, and will successfully usurp the throne from her. If Toriel is dead, then Undyne gets the throne anyway by being third in line.
  • Badass Gay: She's a really tough woman. She also has a thing for Alphys, and asks you to deliver a love letter she wrote to her in the True ending route because she can't muster the courage to do so herself. And if you call her while in the garbage dump, she'll describe it as "a GREAT place to meet girls."
  • Beyond the Impossible:
    • Played for Laughs if fighting her on a non-Genocide run, in which she suplexes a boulder "because she can", then suplexes ten boulders for the same reason, then finally suplexes herself "just to prove nothing is impossible".
    • Played for Drama on a Genocide run, in which she appears to die, but, despite being a monster rather than a human, is capable of amassing enough of her own determination to make a Heroic Second Wind and take on a One-Winged Angel form, melting as she's finally killed for real. Sure, the monsters in Alphys's lab melted too from trying to take in determination, but the important part is that Undyne has enough of her own determination, when it's established that monsters normally can't gather much of their own.
  • Big Freaking Sword: Though Undyne prefers using spears in battle, she keeps a giant sword in her house. Since she believes anime is true, she thinks humans historically have wielded swords up to ten times their size.
  • Black Knight: In her first appearances. Her dark armor covers her entire body, disguising her face. She is almost never heard speaking, giving her a very sinister and mysterious vibe. Naturally, she is incredibly powerful and a major antagonist (being The Determinator that relentlessly chases you through the whole Waterfall zone). Unusually, she uses spears instead of swords.
  • Blade on a Stick: Her weapons are spears, and she seems to be able to summon and throw as many as she wants, often throwing three at once in her normal battle, or summoning up to six through the floor. In her Genocide run form, she can summon dozens of spears at a time. While they appear to be made of water in the overworld, her battle sprites seem to be holding whole spears.
  • Blood Knight: Loves fighting. In fact, it's impossible to spare her when you engage in combat... you have to run away, as she refuses to accept your mercy.
  • Boisterous Bruiser: The loudest and most boisterous in the game.
  • Bootstrapped Leitmotif: She has her own leitmotif, which plays during her introduction, during the chase sequences, and during her boss fight. However, the Ruins leitmotif is more associated with her, playing throughout the Waterfall zone and during her boss fight. The Ruins leitmotif even plays during her death sequence (a clipped version of "An Ending"), her transformation into Undyne the Undying ("But the Earth Refused to Die"), and the battle against Undyne the Undying ("Battle Against a True Hero"), while her leitmotif is absent from those songs.
  • Break the Haughty: She comes into battle composed and determined, fully expecting to win the battle effortlessly... but as the battle goes on, she becomes more and more frustrated at your refusal to die, eventually going from her standard smiling expression to an upset grimace. Her flavor text at this point states that she's hyperventilating, twitching her eye, and wondering if you surviving this long is a prank. And when you save her life by pouring water on her, it's implied her pride is severely damaged by the fact she was just about to die of something as mundane as overheating and was saved by someone she was doggedly trying to kill, making her re-examine going after you. However, she'll still end up on bitter terms with you unless you've played as a complete pacifist and hung out with her.
  • The Brute
  • Cat Smile: After befriending her on a Pacifist run, she usually wears one whenever Alphys comes up in a conversation.
  • Challenge Seeker: Tell her she can't do something. Anything at all. She will do exactly what you say she can't do, or die trying! For example: when she resists befriending you, Papyrus uses Reverse Psychology on her, saying she's "not up to the challenge." After that, she insists on becoming "besties" with you.
  • Chekhov's Gun: Turns out that the very-convenient water cooler in the same room she passes out in Hotland was originally installed by Alphys so she could take a drink when visiting.
  • Combat Pragmatist: Undyne is largely a good-hearted and chivalrous person, but the player's various battles with her demonstrate that she isn't at all afraid to employ dirty tricks if she wants somebody dead. When she initially chases the player, she'll fire projectiles from beyond where they can retaliate, and during the boss fight proper, she'll fling a singular, fast-moving spear whenever she changes your SOUL back to white, which is liable to catch a first-time player used to her slower-moving barrage attacks off-guard. And then there's the battle in Genocide mode, where she abandons any sense of fairness altogether and just goes full Attack! Attack! Attack!.
  • Cool Big Sis: According to their nicknames, Undyne is probably 3-4 years older than Papyrus, and he seems to view her as something like this. She in turn is very protective of him, and it's obvious that despite their bickering, she cares about Papyrus a lot.
  • Cowardly Boss: Inverted. To defeat her peacefully, you have to flee battle and then run away as far as you can before she catches up and continues attacking until she can't go any further.
  • Cultured Badass: Plays a snippet of Alphys' theme on the piano fairly well, from what little you can hear of it. Can make good tea, though the rest of her culinary skills are questionable. She also thinks she's well-versed in human history through no fault of her own, making her an incidental Pop-Cultured Badass.
  • Cute Monster Girl: She is a fish girl
  • Darth Vader Clone: Subverted: she's made out to be one when you first see her in her dark armor and menacing nature as well as The Dragon to the Big Bad. However, she soon turns out to be quite different.
  • Death by Irony: A possible case, depending on the player. Undyne refuses to let Papyrus into the Royal Guard because she believes that his general innocence and unwillingness to kill would make him ineffective at best and put him in danger at worst. But Papyrus' total lack of malicious intent can make him so endearing that even capable players might refuse to harm him purely on principle. By contrast, not only is the method used to spare Undyne unintuitive, her attitude and actions can prompt less forgiving players not to even bother.
  • Defrosting the Ice Queen: It's possible to make it past her mean exterior and become her friend.
  • Determinator: Undyne's defining character trait is how determined she is. She never gives up, not even when she's at the point of getting utterly destroyed.
  • Disc One Final Boss: In the Genocide route.
  • Establishing Character Moment: The cutscene right before her boss fight in a Neutral/Pacifist run. Up until now, her actions and dialogue had made her seem like the standard Black Knight archetype: serious, cold and direct in her efforts to stop the player. Then she suddenly tears off her helmet and goes on a really hammy rant about why the player's existence is a detriment to all monsterkind and how she'll do anything to protect them, all while her real Leitmotif (a heroic and somewhat goofy-sounding theme) plays in the background.
  • Everyone Has Standards:
    • Apparently, she won't fight someone who's on the phone. During the middle of the fight in the Neutral/Pacifist run when Papyrus calls you, she won't attack while you're talking to him. This isn't a matter of Talking Is a Free Action... if you speak with Undyne in the same room after befriending her, she'll say she had to wait because you had a phone call.
    • She also insists on making sure the fight is a fair one: if you fail to block her first attack, she'll remind you how the mechanic works, and if you keep failing, she'll complain that she gave you a spear to block with just to make things fair and become quite frustrated.
    • She also believes in Sacred Hospitality, so as much as she loathes you at the time, she won't attack you while you're at her house (with the exception of the "rematch" that gets triggered if you ARE on good terms with her).
  • Eye Beams: Upon transforming into Undyne the Undying, she gains the ability to shoot energy out of the eye that had been covered by her eye patch.
  • Eyepatch of Power: Just look at her.
  • Fantastic Racism: She has a rather odd love-hate relationship with humans. While it's clear she thinks very little of them, she also watches a lot of "human history" (read: anime) with Alphys, and it's clear that it's an influence in her demeanor. She also mellows her demeanor toward humans on a pacifist run, and on the Genocide run, she realizes that you're just as much a threat to humans as you are to monsters and fights for them as well.
  • Fiery Redhead: She's a Hot-Blooded Large Ham, and her overworld sprite reveals that she's got a big red ponytail under that helmet.
  • Fish People: Looks like a fish when she takes her armor off. Her online handle is "StrongFish91".
  • Gaydar: Amusingly enough, subverted. Despite being a lesbian herself, she is completely clueless to the obvious UST between two of her male subordinates. Even if they hook up (with the player's help), she still seems to think they have a close, platonic friendship.
  • "Get Back Here!" Boss: Inverted by Undyne: if you want to overcome her non-lethally, you'll be the one doing the fleeing, while Undyne shouts at you to hold still so she can kill you.
  • Glass Cannon: Statistically, anyways. She has a very powerful attack score of seven, but her defense score is zero despite all of that heavy armor she's wearing. She has enough health to make up for it, though. Averted during a Genocide route, as she's one of the few things that can take more than one hit from you.
  • Good Costume Switch: When she transforms into Undyne the Undying.
  • Good Is Not Nice
  • Good Is Not Soft: She's eager to destroy those who seek to do evil. Even though she's done a lot of bad things herself, in the name of good.
  • Go Out with a Smile: On the Genocide route, she dies happy believing that her friends will stop you from killing everyone after her death.
  • Guilty Pleasure: Soda. She knows it's unhealthy, but obviously has a craving for it, as she keeps it in her refrigerator.
  • Handicapped Badass: She's missing her left eye, wearing an eye patch over it. Doesn't seem to slow her down much.
  • Heel Face Turn: In a Pacifist run, she becomes your friend. While during a Genocide run, she goes from a Knight Templar who fights humans to a heroine who fights for the survival of both humans and monsters.
  • Helmets Are Hardly Heroic: She's wearing a full helm in her first appearance, but ditches it right before she is fought and never wears it again.
  • Hero Antagonist: She's the strongest monster in the Underground, according to them. As Captain of the Royal Guard, she's something akin to a superhero in the eyes of monsterkind, and fights to protect "everyone's hopes and dreams". She also has no qualms about killing you, so you still have to find a way past her.
  • Heroic BSOD: In most Neutral endings where she's alive, Undyne either swears vengeance on you or forgives you, depending on your friendship with her. However, if your Neutral run ends with Asgore and Mettaton dead, Papyrus explains that Alphys vanished. As a result of losing both Asgore and Alphys, Undyne completely gives up at life, spending most of her time either working at Sans' hotdog stand or laying on his couch.
  • Heroic Resolve
  • Heroic Second Wind: If you kill her during the Neutral route, she shows signs of pulling this, but it turns out to be a mere Hope Spot. During the Genocide route, however, after taking a killing blow directed at Monster Kid, she manages to come back even stronger than before. In both situations, she finally dies when she begins to melt, meaning she had SO MUCH willpower, she was creating her own Determination.
  • Heroic Spirit: Her Undying form is this, literally. She comes back from the dead through sheer force of will, in a final attempt to defeat evil.
  • Hero Worshipper: She seemed to be this in her youth for Gerson, the old turtle archeologist (who was once a hero himself). That relationship wasn't much unlike the current relationship between her and the Monster Kid, as she was also described as being clumsy back then.
  • Hidden Depths: The version of Undyne most people see is a Hot-Blooded anime-loving Blood Knight. Then there's a layer on which she is insightful, gentle and caring. She admires Asgore for his pacifism, doesn't want to let Papyrus in the Royal Guard despite his fighting skills because of his naivete and kindness, and is in love with Alphys for her passion. She won't hurt an innocent... except the protagonist on a Pacifist run, which is a source of great conflict to her. The strange behavior on the date with her just highlights how much of a Moral Dilemma she's been facing with the apparent salvation of monsterkind being killing a kid.
  • Honor Before Reason: Despite wanting your soul, Undyne, during the fight with you, gives you a spear and allows you to save, rather than simply capturing you and bringing you to the King. She's emulating all the anime she's watched.
  • Hot-Blooded: Does absurd things like suplex boulders in the middle of a fight, just because she can. Even her cooking is hot-blooded, making spaghetti sauce by punching the vegetables, and stirring the pot by stabbing it with her spear.
  • Insult to Rocks: Even with her disdain for humans, when she fights you in the Genocide run, one of the lines she uses is "Human... no. Whatever you are...", which seems to have a taste of this to it; she regards you as being even more contemptuous than humans in general, and that's saying a lot.
  • Interface Screw: When your soul is green during her fight, sometimes the next bullet to hit you will be highlighted red. ...Sometimes it won't.
  • Irony: She's a Hot-Blooded Badass Gay Screaming Warrior who also plays the piano... an instrument whose name means "soft" or "quiet" in musical notation.
  • Jerk with a Heart of Gold: She's overall quite mean, but deep down, nothing matters to her more than protecting others. It becomes more literal when the SOULs (which in Undertale are represented by heart symbols) of every human and monster in existence give her the strength to ressurect herself in an attempt to defeat the player.
  • Knight in Shining Armor: Ironically despite fitting all the criteria for a Black Knight, she has the personalty and moral code of this trope. While she is out to kill you, it is purely to free her people, and even then, she's not exactly happy about it. Further, if you become the villain, then Undyne will be the heroine that stands in your way. She's even acknowledged as such in game.
  • Knight of Cerebus: Subverted. She's the first boss character in the game who wishes to kill you, marking a turning point for the tone of the game, and gets quite a lot of build up as someone the human child shouldn't mess with. After you meet her, however, she drops the silent, stoic facade, revealing she's just as prone to the bizarre antics as a lot of the rest of the cast.
  • Knight Templar: She's been hunting humans, taking their SOULs and delivering them to the king. She believes this is the right thing and has complete trust in the king's vengeful mission against humanity. Though the player's actions may cause her to have second thoughts, proving to her that not all humans are bad. During the Genocide route, she has a similar epiphany: in her Undying form, she fights not only for the sake of monsters, but for the good of all of humanity as well. Thus she truly becomes a force of good, rather than just someone who thinks they're fighting for good.
  • Leitmotif: At first, "Undyne". After she unmasks herself, it's replaced by "NGAHHH!!"/"Spear of Justice". As the Undying, she gets "Battle Against a True Hero" as her battle theme.
  • Lesbian Cop: She's a Badass Gay who is also Captain of the Royal Guard. In addition to human-hunting, she also acts as law-enforcement.
  • Lethal Chef: In her date event, she attempts to cook pasta. Her methods involve punching the veggies for the sauce, stirring a pot with her spear attacks, and amping the fire in the stove until house burning levels. Apparently, anything besides brewing tea is beyond her abilities.
  • Let's Fight Like Gentlemen: She wants to defeat you fairly, so she gives you a spear at the beginning of the battle to block her attacks. If you repeatedly fail to block her first attack, she gets extremely pissed off over you being such a worthless opponent, and unleashes an extremely brutal flurry of attacks.
  • A Lighter Shade of Black In the Genocide route, she's still a Knight Templar with Fantastic Racism against humans, but she has the moral high ground against the Ax Crazy Villain Protagonist player.
  • Like Brother and Sister: Her relationship with Papyrus falls squarely into this.
  • Logical Weakness: A water dweller wearing full plate armor that heats up easily? Of course, she doesn't do too hot in a volcano area...
  • Lonely Piano Piece:
    • In a Neutral run, a clipped version of "An Ending" plays once you have depleted Undyne's health, but before she dies. This hammers in the fact that she is going to die, no matter how hard she tries to pull herself back together with Determination.
    • On a Genocide run, the triumphant "Battle Against a True Hero" plays. It has a piano segment that sounds like a feeling of hope that is false.
  • Making a Splash: The spears that she summons appear to be made of water.
  • Masculine Girl, Feminine Boy: The masculine girl to Papyrus' feminine boy.
  • Mercy Rewarded: "Defeating" her on Pacifist run requires running until she collapses from exhaustion, and then giving her water. She's a lot more cordial later.
  • Memetic Sex Goddess: Nearly to Toriel levels, in fact.
  • Monster Knight: Quite literally. She is a monster and a knight, and she has the sense of honor and justice that comes with the description.
  • Non-Mammal Mammaries: When she is out of her armor, she has a visible, albeit small, bust.
  • No Sell: She's so determined to capture you that even the debug command that makes monsters instantly spareable doesn't work on her.
  • No Social Skills: The two of you hanging out starts with her breaking her table in half with her spear when you try to select a beverage, and ends with the two of you accidentally burning her house down while trying to make spaghetti.
  • One-Note Cook: Her overexuberance leads to disaster when she cooks, but her tea is specifically noted to be good, though too hot to drink properly when you first get it.
  • One-Winged Angel: As Undyne the Undying. Her attacks get more complex, deal far more damage, and move much faster. She also switches the player's SOUL color between red and green more often, and the player is prevented from escaping the fight.
  • Peek-a-Bangs: In her casual outfit, she has her hair covering her bad eye instead of an eye patch.
  • Pet the Dog: Several cases where she does this.
  • Platonic Life Partners: She's huge friends with Papyrus, but they're clearly only friends, and it's enforced by the fact that Undyne's a lesbian.
  • Playing with Fire: Examining her stovetop during the child's visit to her house will prompt Undyne to remark that despite the wonders of technology, flame magic-cooked food beats the stove when it comes down to it, so she might have access to such magic or possibly when Asgore makes a visit. Regardless, she pulls this trope literally, cranking the heat up on the stove to needless levels and promptly burns her house down when it explodes in her face.
  • Power Incontinence: In her normal boss battle, once you deplete her HP, she lingers around, requiring a few more attacks to fully defeat her. While this happens, her body begins wavering in and out of focus. Her will to stay alive is strong enough to generate Determination, but without the realization that you are a threat to the entire world giving her the final push, she simply can't muster enough of it to stave off death. The result is only a partial transformation (her visible eye's colors invert), and she begins to melt before disintegrating into dust.
  • The Power of Friendship: Professes this to cheesy anime levels.
  • Punny Name: Undines are mythological elemental creatures of water. Undyne is a fish looking monster who lives in a house that also looks like a fish. It's also a play on "Undying", which comes into play when you fight her on a Genocide route.
  • Rasputinian Death: In the Genocide route.
  • Sacred Hospitality: Sure, she's antagonistic with you until her house gets burned down, but you're not going to get up for anything as long as you're a guest in HER house.
  • Serious Business:
    • Exploited when befriended. When Papyrus tries to set up the player and her as friends, she refuses. Papyrus plays it up as a challenge, she does it for the need to win.
    • Anime, which she mistakes for examples of actual human history. When you finish Alphys's friendship-making sequence, she's conflicted over whether anime is real or not. You can either tell her that "anime is real", and she gets pumped over the idea of becoming a Hot-Blooded shounen anime protagonist, or you can tell her "anime is NOT real" and crush her dreams.
  • Sir Swearsalot: The level of language in Undertale is pretty conservative to begin with, but Undyne is the most crassly-spoken among the cast.
  • Statuesque Stunner: She's among the tallest of the characters, only after Asgore, Mettaton and Toriel.
  • Stealth Pun: She's a kind of fish-monster who fights using spears. A spearfish.
  • Straight Gay: Aside from the occasional Ship Tease, the only way to get a clear hint of her lesbianism is if you try calling her from the garbage dump, where she talks about how it's "a good place to pick up chicks", with a clear air of personal experience. And the only way to confirm it is by playing the Pacifist route, where she eventually recruits you to help win Alphys' heart.
  • Tactical Suicide Boss: Well, not exactly suicide. During the battle, she can smack your SOUL with her spear to switch it from green to red and vice versa. She intends for this to allow her to use a second attack pattern, but she forgets something... the red SOUL has the ability to run from battle.
  • Taking the Bullet: On a Genocide route, Undyne takes the bullet for the Monster Kid when the player attempts to kill the Kid. This allows her to turn into Undyne the Undying moments later.
  • Technically a Smile: She tends to show these when her plans derail or something unexpected happens. During the first third of your time hanging out with her, she shows one constantly which makes her, as you know what she is capable of, extremely scary as you are constantly afraid that she will impale you with a spear.
  • Teleportation: She seems to have some sort of teleportation ability... notice how she just vanishes into the darkness with a "magical" sound effect after you first see her. She doesn't use it nearly as liberally as Sans though.
  • This Is Unforgivable!: Won't befriend you if you've killed any monsters beforehand (and explicitly mentions if Papyrus doesn't show up to his meeting with her...), and killing anyone after befriending her will cause her to hate you far more in the ending phone call than she would if you had just killed people.
  • Toilet Humor: Loves this. Particularly notable is her puzzle idea of "timing pukes".
  • Tomboy: She partakes in male-oriented activities and has all the masculine gender roles you can think of.
  • Tomboy and Girly Girl: Tomboy to Alphys' girly girl.
  • Tsundere: She acts extremely aggressive in order to cover up her softer side. The "dere" side is mostly reserved for Alphys. She also shows some of her softer side with Papyrus, though platonically.
  • Wake Up Call Boss:
    • She's the first enemy you see that's actively trying to kill you, and it shows! She's much more difficult to deal with than Toriel and Papyrus. The method of sparing her is quite unorthodox as well. That is to say, you can't spare her. You run away.
    • She's also this if you're attempting a Genocide run. Players expecting her to get one-shot like every other enemy in a Genocide run are going to be in for one hell of a surprise.
  • Who's Laughing Now?: Her story of being humiliated by others for losing a fight against Asgore can be inferred as this, as said fight led to her promotion as captain of the Royal Guard.
  • Yandere: She doesn't lose her violent self when you try being her friend.

Alphys

Oh. My god. I didn't expect you to show up so soon! I haven't showered, I'm barely dressed, it's all messy, and...

The king's chief scientist. She's a socially awkward monster who loves anime, and also has prodigious engineering capabilities. She helps you traverse Hotland.

Tropes exhibited by this character include:
  • Adorkable
  • Anti-Heroine
  • The Apocalypse Brings Out the Best In People: During the Genocide run, she spends her time working behind the scene to evaucate as many monsters as possible to the True Lab. If you abort the Genocide run in Hotland, then she succeeds in saving Monsterkind and is both hailed as a hero and elected to be the new ruler.
  • The Atoner: Becomes this in every ending in some capacity. At the very least, she'll admit to you that you'll need to kill Asgore and take his SOUL in order to escape the Underground in most Neutral routes, confesses to everything she did in the True Labs in the Pacifist run, and in the near-Genocide Neutral ending, she evacuates the surviving monsters and becomes the ruler of the Underground (and is implied to have confessed her secrets in this ending as well).
  • Barefoot Cartoon Animal
  • Bitch in Sheep's Clothing: Downplayed, she IS a legitimatley good person, but her assistance of the player was initially an act. This goes away comoletley after a Pacifist route.
  • Bi The Way: Has crushes on both Asgore and Undyne at the same time.
  • Break The Cutie: It's a long process for poor Alphys. She was quite crumbly from her backstory failures with the Determination experiments, who left her considering suicide, but the in-game events renew the breaking again. It starts when Mettaton sabotages her attempts to save you from danger that she herself set up, causing her to suffer a lapse in the confidence she's just recently built by saving you before. It gets worse when Mettaton reveals she's been deceiving you, and that he's done playing around, causing her to have a full breakdown. And that's not even getting into the True Labs, where the results of her experiments on Determination show their face. It's no wonder that, on some routes, Alphys can commit suicide out of grief.
  • Butt Monkey: Nothing goes well for thr poor doctor.
  • Chekhov's Gunman: It's possible for Alphys to mistakenly call you to order pizza way before you meet her.
  • Cool Big Sis: According to Bratty and Catty, Alphys used to be this for them.
  • Cute Clumsy Girl
  • Cute Monster Girl
  • Did I Just Say That Out Loud?: While "romantically roleplaying" as Undyne with her, regardless of your choices, she ends up going completely overboard and yelling at the top of her lungs. This gets the attention of the real Undyne, who'd been looking for her by that point.
  • Does Not Like Shoes
  • Dub Name Change: The Japanese translation of the game drops the 's' from her name, making her simply 'Alphy'.
  • Early Bird Cameo: A random one can happen if your FUN value (a line of code which is randomly assigned when the game files are created) is a certain number, and has Alphys calling you as early as leaving the Ruins, having dialed the wrong number and thinking she has a pizza place. This also happens if you befriend her on a pacifist run, but reset before doing the final bosses.
  • Expy: She's basically the sexy genderbent version of Francis from Super Paper Mario.
  • Fat Bastard: She tried to help, you, yes... from obstacles she herself set up.
  • Fat Best Friend: Of Undyne, at least.
  • Genius Ditz
  • The Ghost: In the Genocide route, she's said to be evacuating any and all survivors someplace safe and out of your reach, and as a result, most of Hotland is completely shut out to a Genocide player. She can only potentially appear if you get pushed into the Neutral path in Hotland or the CORE (by sparing one or two key encounters, or not exhausting the random encounters there, but still killing Mettaton), at which point Sans will end up putting her on the phone for you. However, she does this only to tell you that you're a monster and that she hates you.
  • Grew a Spine: If the protagonist is on the Genocide route, Alphys finally gathers the courage to leave her lab and get as many monsters to evacuate as possible. If you abort the Genocide run in Hotland, the Neutral ending involves Sans giving the phone to Alphys, who discusses how she finally had to become brave and become the new ruler of the (remaining) monsters.
  • Having a Blast: Since her attacks (as a Lost Soul) are the same as Mettaton's, she uses bombs in one of her attack patterns.
  • Interrupted Suicide: It's implied that at one point, she was suicidal. Undyne first met her in the dump staring into the abyss and looking "contemplative". Undyne managed to talk her out of it though.
  • Intrigued by Humanity: Loves anime and joined a human fan club.
  • Labcoat of Science and Medicine
  • Leaning on the Fourth Wall: The way that Mettaton describes Alphys watching the player and "yells at the screen" can be seen as a playful jab at Let's Play video audiences, and the way she continually attempts to influence your playthrough can be seen as a commentary on backseat gaming as well.
  • Lizard Folk: She's a monster that looks like a reptilian humanoid.
  • Luminescent Blush
  • Meaningful Name: Her name is a meaning for being intellectual and having interest in research. It also can be an anagram of 'Shy Pal' or be a conjunction of 'Algebra' and 'Physics'.
  • Mission Control: She acts as this throughout Hotland, frequently calling you and giving you remote help from her lab.
  • Morality Pet: For Mettaton. It eventually becomes clear that, for all his bragging, snark at her expense, and occasional frustration with Alphys, he really does care very deeply about her, and is incredibly grateful for her role in making him famous. In the Neutral route ending where he winds up in charge of the Underground, and Alphys has gone missing (implied to have committed suicide), he expresses regret, saying he wanted her to rule with him, and erects a statue of her. In short, Mettaton's friendship with her is easily one of his more redeeming qualities.
  • Memetic Sex Goddess: Albeit mostly in fanart.
  • Motor Mouth: Whenever Alphys brings up anime that she likes, she has a tendency to ramble on without pause until she catches herself (in hilariously stark contrast to her usual stuttering and stammering). The last time she does it plays this for drama on the True Pacifist run when Alphys confesses to Undyne that all the "human history" they watched together was nothing but nerdy cartoons.
  • Nerd Glasses: She wears glasses, she's a scientist, and she avoids talking to others.
  • Nerds Are Sexy: Hard for her to not count as this when you consider that Undyne is attracted to her.
  • Only Sane Woman: She's the only one who doesn't try to fight you during the Genocide run.
  • Otaku: She rarely gets out of her lab, is obsessed with anime, comics and video games, and even has cups of instant noodles in her fridge. She has passed some of her otaku-ness to Undyne, who will beg the player to answer if anime is real at one point.
  • Red Oni, Blue Oni: Blue to Undyne's red.
  • Robosexual: Implied. She keeps anime of robots making out saved to her phone for some reason, and she had trouble finishing Mettaton's EX body because she got "really sweaty" whenever she tried to work on it.
  • Shock and Awe: During the ending sequence of a Pacifist run, she blocks Flowey's attack with a wall of electricity.
  • Shrinking Violet
  • Significant Anagram: Possibly unintentional, but "Alphys" rearranged can be "Shy Pal", which describes her perfectly: a socially awkward individual who just wants to be the protagonist's friend.
  • The Smart Gal
  • Socially Awkward Heroine
  • Speech Impediment: Stutters even more than Lammy from Um Jammer Lammy.
  • Stop Helping Me!: Alphys is a little overbearing when it comes to trying to help you during your journey. Eventually, you learn that most, if not ALL obstacles she helps you with were designed by her, and she's helping you in order for you to feel grateful and appreciate her. She's also actively working for the king and she's leading you to him by the king's order.
  • Tertiary Sexual Characteristics: Enforced. In the artbook, it is stated that Alphys was originally planned to be male, but Toby Fox disliked the idea in the end, and ended up adding eyelashes onto her.
  • Tomboy and Girly Girl: Girly girl to Undyne's tomboy.
  • Trademark Favorite Food: She enjoys instant noodles and other junk food, judging by her fridge. Makes sense when she needs to work on her experiments, or spends hours watching anime.
  • Visual Pun: At one point in her dating scene, she gets thrown into a trash can by Undyne, rendering her literal anime trash.
  • Walking Spoiler: Anything relating to her real motiviation for helping you in the Hotland portion of the game, and especially the True Laboratory and her past cements her as one of these.
  • Wingding Eyes: Alphys also has hearts in her eyes when she thinks Undyne is going to train her.

Mettaton

OOOOOOOHHHHHHH YYYYEEEESSS!!!!!!!!!!

An entertainment robot who also happens to be programmed to kill human beings. As a result, his shows are inclined to take a murderous turn whenever any humans are involved. He isn't actually a robot, but rather a ghost that possess the metal bodies Alphys built him.

Tropes exhibited by this character include:
  • Affably Evil: Can actually be a pretty fun guy when not trying to murder you veers into Faux Affably Evil during fights though
  • Alas, Poor Villain: On the Pacifist route, Mettaton ends up in a near-broken state. He then receives calls from viewers, who tell him how much they love his performances and how it has made their lives happier.
  • Ambiguously Gay: Despite his camp behaviour, he's probably asexual, due to being a robot.
  • Arc Villain: He is this in the Hotland section of the game, especially when he takes his kid gloves off and starts hiring other monsters before trying to kill you himself.
  • Awesome but Impractical: In-Universe, as he clearly likes his Mettaton EX form very much, but due to the form's "inefficient" power usage, he can't stay in the form for very long until his battery power conks out. He gets better by the end of the game after getting fixed by Alphys. It's still unknown if the power problem got fixed or not.
  • Bad Boss: According with Burgerpants, he is extremely strict. Other employees say that he complains and tantrums when things are not to his taste.
    • Benevolent Boss: Talking with his employees after killing him in a Neutral route, however, paints him as a guy that, while overbearing, was actually kind and encouraging, giving some monsters with impediments an actual chance of achieving their potential and deliberately minimizing the amount of puzzles on his Resort to give his visitors a break.
  • Big Bad Ensemble: With Asgore. Asgore is the king of the monsters and the overall threat, but Mettaton is a reccuring antagonist throughout the game and is actually responsible for many of the bosses you fight during the game. It's only after beating Mettaton that you fight Asgore.
  • Camp Gay: He likes to call people "darling" and has a flamboyant attitude. At one point, he transforms into Mettaton EX, who is definitely... fabulous.
  • Cat Smile: He pulls a few smug ones here and there in his EX form.
  • Chainsaw Good: He seems to enjoy them enough to feature them regularly in his cooking show.
  • Deadpan Snarker: To a truly hilarious degree. He'll never let an opportunity to snark at Alphys' or the protagonist's expense pass by him.
  • Dissonant Serenity: Act like a hammy, snarky tv host. And does so trying to kill a child.
  • Dragon-in-Chief: Is revealed to be working for Alphys, but is still clearly the stronger of the two; he then ends their partnership and carries on with his own plans before his last boss fight.
  • Early Bird Cameo: Papyrus' randomly generated maze puzzle is Mettaton. This is more noticeable if you go back to see that it's gone. This also changes the context of it "messing up"... it wasn't a technical error, it was Mettaton screwing with Papyrus.
  • Even Evil Has Standards: Say what you will about his morals, but it's revealed before his boss fight he doesn't actually hate humanity and desires to stop Asgore from starting the war. He would be an outright Well-Intentioned Extremist if not for his ego.
  • Even the Guys Want Him: Oh, yes. Papyrus calls him his "favorite sexy rectangle", and remarks that he wishes he lived in Hotland so that he could meet him. This is after Papyrus mentions about three times before how glad he is he doesn't live there...
  • Evil Counterpart/Foil: To Papyrus (they even get one or two Ship Tease moments with one another). Both have huge egos, and both act extremely campy and over the top. However, Papyrus is very low level despite having high ambitions. Mettaton has a very high position in society. Papyrus is described as a "human hating fanatic" by Sans and actively hunts you, but Mettaton is revealed to not have anything against humanity and has separate goals. Also, whereas Papyrus worships Undyne and strides for her approval, Mettaton and Undyne seem to have a rivalry. The biggest difference is that while both have egos and large ambitions, Mettaton is willing to kill to fulfill his goals, while Papyrus will stop himself before taking things that far.
    • He could also be considered one for Undyne. Undyne is a stern (if hammy) Knight Templar with extreme loyalty to Asgore. Mettaton is an over the top ham-fest who has nothing against humans particularly and has separate goals from Asgore. Tellingly, they're rivals.
  • Evil Gloating: Seems to enjoy doing this quite a bit.
  • Exact Words: Because you defuse all six of his lesser bombs, the Big Bomb will not go off in 2 minutes. It will go off in 2 seconds.
  • Faux Affably Evil: Mixed with Affably Evil, but they have an absolutely jovial and over the top sense of humour and displays it while trying to murder you, a small child. It stands out the most with his "box office bomb" joke.
  • Face Death with Dignity: If you kill him on a Neutral run, he'll Go Out with a Smile, coolly (and dishonestly) saying Alphys can fix him and wishing the player luck, thanking them for giving him the chance to "perform" for them. Even when you one-shot him in a Genocide run, he'll go out with a smirk and a dry one-liner (or mocking you, if you flubbed the requirements for a Genocide run at the very last point where it's possible to do so). On the Pacifist run, he acknowledges that his EX form has a Fatal Flaw in its poor battery life (not that the batteries can't be replaced until Alphys fixes the problem off-screen later). He postpones his debut in the human world to remain a cultural icon in the underworld, thanks everyone for tuning in, and lets his battery life finally run out.
  • Foregone Victory: You cannot actually lose during his quiz; his penalty attack always inflicts half of your HP rounded down in damage and thus cannot actually kill you. You also cannot die to any of his subsequent challenges along the way to the MTT Resort; if you fail, either he does something that spares you at the last second (such as abruptly going to a commercial break) or Alphys steps in to save you. As it turns out, this is all because Alphys and Mettaton rigged the entire journey so that she can come off as a hero. Mettaton's EX form averts this trope, as by then, he's gone against Alphys's plans and is trying to kill you for real. Played straight once more with Mettaton NEO, as he not only goes down in a single attack, but also doesn't even bother to attack you.
  • Foreign Culture Fetish/Intrigued by Humanity: His hotel and his media empire are modeled after human styles and star system. When stuff isn't to his taste, his first complain is "this is not how things are done in the Surface." This is the main sign that Mettaton isn't as human hating as he has been painted by Alphys.
  • Four-Fingered Hands: With White Gloves. Word of God says he's confused over how many fingers humans usually have because all of his knowledge comes from media, including Western cartoons. He actually has several gloves with different numbers of fingers.
  • From Nobody to Nightmare: In the King Mettaton ending. Goes from a nameless snail farmer to a tyrannical king.
  • Glass Cannon: Mettaton Neo: 90 ATK. 9 DEF. He dies in one hit; if you failed the Genocide requirements at the end of his battle, he even lampshades it as he dies by saying that Alphys should maybe have worked a bit more on his defences. Subverted, as he doesn't even attack you, thus rendering his stats irrelevant.
  • Glory Hound: A very sympathetic version. Since he still gets a soul by killing you, he knows that he'll be able to get through the barrier and get fame in the human world as a hero. He does honestly want to help both species, and by helping his ratings, you get him to realize you're a worthy hero to stop the war yourself and people already appreciate him, so he allows you to go on in peace.
  • Graceful Loser: In the Neutral and Pacifist routes, he takes his defeat remarkably well. In the Pacifist route, he even has a bit of a So Proud of You moment.
  • Having a Blast: He loves using bombs against you, both in the newscaster segment and in battle.
  • Heart Drive: His heart-shaped core.
  • Heel Face Turn: In the Pacificst run and even in a Neutral run, his last words before shutting down are motovating you to defeat Asgore.
  • Heroic Sacrifice: In the Genocide run, it's implied that part of his real reason for fighting you, even though he knows he can't win, is to allow Alphys and other monsters to escape.
  • Hour of Power: His EX form has inefficient battery consumption, meaning he'll eventually run out of power (and lose his limbs) if the fight drags on.
  • Impossibly Graceful Giant: He's not exactly gigantic, but he's incredibly agile and graceful for a metallic robot.
  • It's All About Me: He's ridiculously egotistical and self-indulgent. If he becomes king, he makes the Underground into an Egopolis.
  • Large Ham: Easily outperforms Papyrus and Undyne in this department. Then again, he is an entertainment robot...
  • Leitmotif:
    • "Metal Crusher" is his standard battle theme, "It's Showtime!" sounds for his intro cutscene and cooking show, and "Oh! One True Love" reappears as "For The Fans".
    • "Death by Glamour", his boss fight theme, draws from both of them. It can actually can be heard in the game long before the actual fight with him. The opening part is heard in the opening of CORE, the "chorus" can be found in the "chorus" of his previous theme "Metal Crusher", and the bridge can be heard in "It's Showtime!", "Live Report" and "Death Report".
    • While he has "Power of 'NEO'" for his NEO form, it's really just a remix of "Battle Against a True Hero".
  • Lightning Bruiser: Bordering into Confusion Fu territory. Mettaton's battle style is unusual and based on being varied, fast, and flashy to entertain viewers first and foremost. Trying to both entertain and battle, he's a competent fighter.
  • Mad Bomber: In his 'Newscaster' scenario, he traps you in an area full of bombs disguised as several seemingly innocuous things, like a glass of water and a dog. In his EX form, many of his attacks involve bombs as well.
  • Mean Boss: When it comes to Burgerpants in any case, not so much towards his other employees. He made a whole album purely dedicated to telling Burgerpants how bad at his job he is.
  • Meaningful Name:
    • True to his occupation, Mettaton is very much aware of genre expectations and the fourth wall as it exists in the game. A ton a' meta, in other words.
    • His name could also be a reference to Metatron, an angel whose name abbreviates to MTT and who was a human before being transformed into an archangel.
  • Memetic Sex God: For pretty obvious reasons when he's in his EX form despite the obvious fact of him being a robot. Albeit in-universe, he is considered this even in his rectangular form.
  • Mirror Boss: Notable for being the only boss that has a SOUL present during the fight itself. In a reversing of roles, you can attack it just like how bosses attack your SOUL.
  • Morality Chain: It's implied that Alphys is one of these to him, as shown in one of the Neutral endings. In particular, the Neutral ending where he becomes tyrant ruler of the Underground has him mention that he wanted Alphys to help him rule, only to discover that she went missing. It's heavily implied that, had Alphys not disappeared and possibly committed suicide, Mettaton would have become a much better leader due to her advice.
  • Mr. Fanservice: In his EX and NEO forms, at least.
  • Multiple Choice Past: Depending on what route you took. In a Neutral/Pacifist run, he was made as the entertainment-type rectangular robot and upgraded to his EX form later. In a Genocide run, he was created as an anti-human robot first, then given his rectangular form later when he was re-purposed as an entertainment robot. Of course, his speech in his Genocide encounter could be baloney. He takes a noticeable pause when he describes his rectangular form as "more photogenic" and despite having a fierce and imposing-looking appearance, doesn't attack you at all. Also, why would his old form be called 'NEO' (new)?
  • My God, What Have I Done?: If you spare him, he receives a call from Napstablook and clearly feels guilty about leaving them behind. It happens again in the Neutral ending variant where he becomes king of the Underground; with Alphys "missing", he expresses regret over how he treated her.
  • No, You: If you throw out an insult or cuss-word during the essay portion of his last battle, he throws it back in your face with "This essay is supposed to be describing me, not you."
  • Oh Crap: Has a mild version of this when his limbs blow off during your fight. He tries to play it off as a Major Injury Underreaction, but his stuttering gives him away.
  • One-Wheeled Wonder: In his usual appearance, where he balances his rectangular body atop a single comically tiny wheel.
  • OOC Is Serious Business: Mettaton during your last fight against him. He starts as his usual self shamelessly proclaiming himself the brightest star of underground and soon-to-be of the surface. As the battle drags on, he'll start to lose his composure and outright call the player out for their "weakness". Also in the ending where he rules the Underground, he becomes somber and saddened over Alphys' disappearance and wishes he had a chance to treat her better.
  • Percent Damage Attack: The penalty laser he uses during his quiz halves your HP and as a result cannot actually kill you.
  • Pragmatic Villainy: Mettaton's primary concern is his audience, which is more important to him than killing you. Though he multi-tasks quite well...
  • The Reveal: Buying the Mysterious key the Alley Girls sell and using it in the closed house right to Napstablook's reveals that Mettaton was a human-admirer ghost with show business ambitions.
  • Shaped Like Itself: The game occasionally gives scent-based information in the status window, such as saying that Papyrus "smells like bones". All the game can muster for Mettaton is "smells like Mettaton".
  • Shock and Awe: Mettaton zaps you with electricity if you get a question on his quiz wrong. Mettaton EX's heart sprays out lighting when it attacks directly.
  • Stealth Pun: Mettaton, the celebrity, has a NEO form that only appears for a short while on a Genocide route and is then forgotten entirely as he's killed in a single strike, and the player heads on to Asgore despite the unique battle theme and buildup. Talk about a one hit wonder.
  • Tactical Suicide Boss: In his EX form, Mettaton has a weak point in the shape of a heart not unlike a human SOUL... which he'll reveal in order to make puns and attack with it, allowing your yellow SOUL to shoot it. Note that this doesn't actually kill him (that can only be done by physically attacking); its only purpose is to knock off his limbs and lower his desired ratings count.
  • There Was a Door: How he makes his entrance at Alphys' lab, with unexpected grandeur. Checking the hole he made in the wall reveals the space inside it is actually quite small, implying he was camping out inside Alphys' wall the entire time she was talking to you beforehand.
  • Threshold Guardian: Mettaton is an unusual variant of this trope, as you fight him very late in the game, but he isn't a threshold guardian to a heroic adventure... he's a threshold guardian to the Genocide run. If the player is having second thoughts about killing everyone in the game, Mettaton's NEO form is the player's last chance to back out... if the player fails to kill enough Hotland encounter monsters (around 40) before fighting him, Mettaton decides you're not irredeemable and sets you on Neutral instead.
  • Unexpected Shmup Level: Or rather, Unexpected Shmup Boss. The yellow SOUL feature you get from Alphys gets used more extensively in the fight against Mettaton EX, where you have to shoot his bombs, legs and soul to fight back... the only time in the game where you have any sort of direct offensive capability on the bullet board.
  • The Usurper: In the Neutral ending where he becomes ruler, Sans states he "just kind of... took over?". By contrast, the other characters who become ruler in the Neutral endings either inherit legitimately (Toriel, Undyne) or are elected by popular support (Papyrus, Annoying Dog, Alphys).
  • Viewers Are Geniuses: In-Universe: considering Mettaton's infamous train question...
  • Voice Grunting: Stereotypical robot beeping.
  • World of Snark: His TV shows seem to be this, if what the human child goes through is any indication.
  • Zero Effort Boss: Justified: Mettaton NEO is the most standout example on the Genocide run. Not only does he go down in one hit, he never attacks. That's because he's not there to FIGHT you, but to STALL you to buy the evacuation more time. It's even in his battle stance.

Asgore

Human... It was nice to meet you. Goodbye.

King of the monsters. Asgore Dreemurr cares deeply for his subjects and is prepared to do anything to free his people, whilst protecting them from humans. He bears a serious grudge towards humanity, for several reasons, thus he decided to start collecting human souls which, if enough are collected, could elevate him to godlike status, in order to enact vengeance against mankind. He actually doesn't want to enact revenge on humans, much less killing them, but he feels compelled to do so anyway, as a way to make his people hopeful.

Tropes exhibited by this character include:
  • Affably Evil: He offers you tea, before realizing that there's no time for that. He also asks you if you're ready before you fight him, and apologizes for what follows, then says "goodbye". He's actually not evil at all, but a Nice Guy, and all the monsters think so as well. But he is a tragic character who goes great lengths to achieve what he feels would make all the monsters happier, even when he knows it's wrong.
  • Anti-Villain
  • The Atoner: Seems to be set on making on things right in the True Ending.
  • Authority Equals Asskicking: He's not the King of Monsters for no reason.
  • Badass Baritone: Has easily the deepest Voice Grunting in the game, implying an equally deep voice.
  • Badass Cape: Wears a rather long one.
  • Barefoot Cartoon Animal
  • Beware the Nice Ones: It's said that he's the most gentle-hearted monster in all the Underground, and he is. However, once he's resolved to fight, he's an absolute terror. Even Undyne has only ever managed to knock him down once, when he trained her to be able to beat him, if that tells you anything.
  • The Big Guy
  • Blade on a Stick: His weapon of choice is a giant crimson trident, which has a flower carved onto it.
  • Boss Remix: "Bergentrückung", his normal theme, gets a bit more kick to it as "ASGORE" once he starts his battle.
  • The Brute: Of the Dreemurr family.
  • The Chains of Commanding: He has no more interest in killing you or waging war on humanity, but since the promise that monsterkind will someday return to the surface and exact revenge on the human race is the only thing keeping morale up, he feels that he has to.
  • Damage Sponge Boss: There are no tricks to Asgore's fight; he smashes your MERCY button, making him impossible to spare. While there are a couple ways to make the fight easier, ultimately all you can do is dodge his attacks and swing away until he goes down. If you've been entirely pacifistic up to that point, you'll be there a while because you'll only be chipping away a tiny amount of his HP with every hit.
  • Does Not Like Shoes
  • Embarrassing Nickname: King Fluffybuns, as he is called by Gerson and used to by his ex-wife Toriel.
  • Face Framed in Shadow: An unusual example. His face is not visible during the battle because he is looking at the ground instead of at you the whole time. He can't bring himself to look you in the eyes.
  • Final Boss: Hyped up as this throughout the game, but it's ultimately subverted, regardless of the route.
  • Final Exam Boss: Many of Asgore's attacks are very similar to Toriel's, in addition to heavily using variations of blue/orange attacks, introduced by Doggo.
  • Forced Into Evil: It's implied he can't give up his goal to break the barrier with the human souls even if he wanted and how badly he does, or else his people will lose hope of ever escaping the underground.
  • Game Over Man: Asgore can be found saying something every time you die. In fact, it's implied via a cut song and a part within his battle theme that the song that plays while within the Game Over screen is supposed to be his theme song.
  • Gentle Giant: Dwarfs everything else in the game (including Undyne) and is the most gentle and passive character in the game. That is, unless you have to fight him.
  • Giver of Lame Names: As Gerson puts it, "Ol' King Fluffybuns can't name for beans!". Every location in the game was named for him, and he went for the Exactly What It Says on the Tin approach. Not even his child escaped it: he just mashuped his name and his wife's and called a day.
  • Go Out with a Smile: Should you choose to finish him at the end of his battle, although you can see his pained expression as if he's trying to atone for his mistakes. If you fight him again in a Neutral run and spare him, he will be Driven to Suicide, but this time, it's a genuinely hopeful smile that you would find a way to free monsterkind.
  • Heel Face Turn: During a Neutral run, combined with another trope. Also occurs at the end of a True Pacifist run, where he abandons his plans and becomes a friend to the player.
  • Hidden Depths: Asgore is completely unsurprised when you tell him he's already killed you multiple times. It's never explained why.
  • Hidden Eyes: Once his fight begins, he never once makes eye contact, probably because he feels he's forced to kill you and doesn't really want to.
  • Hope Bringer: To all the Underground, it's unanimous: King Asgore is their greatest hope for freedom. And dear lord, does this tear him apart inside.
  • HP to One: Getting hit by any of his attacks will never leave you with less than 1 HP, unless it's at 1 already.
  • Immune to Flinching: He won't move, shake or flinch at all when you hit him. With the exception of when you get his health low enough.
  • Interface Screw: His first aggressive action when the fight begins is to destroy your MERCY option, making it clear that he won't be talked down.
  • Ironic Name: For a guy called Asgore, he's not very comfortable with having blood on his hands.
  • Kill All Humans: Seems to be his ultimate goal. Very, very much played with: at first, he's all for this, but after calming down from his initial need for vengeance, as well as either directly or indirectly causing the deaths of six humans, he's become extremely disillusioned, and while it IS his goal, he does NOT want to do it.
  • King in the Mountain: Asgore is a direct reference to the motif, being completely inactive until the player arrives for their final battle. The intro song to his battle references it by name: "Bergentrückung", the German expression for the "King in the mountain" concept.
  • Knight Templar: He deems his actions as necessary for the prosperity of all monsters, but it's clear he'd end up likely causing even more suffering if his plan succeeds; his war against humans would give mankind more reasons to fear and hate monsters.
  • Large and In Charge: He's extremely tall and bulky, taking up most of the screen that isn't part of the combat menus, though his wife is only slightly shorter than him; presumably, it's just a trait of his species.
  • Lightning Bruiser: Despite how massive he is, Undyne makes a very telling comment during her narration about never landing a hit on him; however, because of the way the battle system is set up, it's stuck as an Informed Ability (though in one of his attacks where he directly swings his weapon, every swing is executed in full in under half a second).
  • Meaningful Name: Asgore Dreamer. He's known for his dream more than his person.
  • Names to Run Away From Really Fast:
    • Just listen to his name: Asgore... Can you imagine what a guy named that could do to you? And the not-so-funny part? He really can do what you just imagined to you, though he'll hate that he has to do it and will do his best to stave it off for as long as possible...
    • "Dreemurr" is an anagram for "Murderer", though whether this actually qualifies is debatable.
  • Nice Guy: He once was, before the loss of his children. He still shows shades of this afterwards, and goes back to being a nice guy at the end of the True Pacifist route.
  • Orcus on His Throne: Despite being the most powerful monster in the Underground, he waits for you to approach him, since he guards the barrier. Turns out to be more because he doesn't want to kill you in the first place.
  • Prongs of Poseidon: Wields a transforming trident that's longer than he is tall.
  • Redemption Equals Death: During a Neutral run. Luckily, this trope is averted during a True Pacifist run.
  • Reverse Grip: Asgore holds his trident with the prongs in the opposite direction from both thumbs, which makes sense considering how he stabs downwards on the MERCY button when the fight begins. However, when he starts swinging it around, he switches to a forward grip.
  • Satan Is Good: Sort of. While he is never explicitly stated as such, Asgore, with his goat-like body, pitchfork weapon, fire spells, and penchant for collecting souls, definitely gives off a superficially Devil-ish vibe. He is also one of the nicest, gentlest characters in the game, who only wants to collect your soul so that he can free his people, who were unjustly sealed away in the underworld by the humans who feared them.
  • Saving Christmas: He dresses up as Santa to spread joy to young monsters everywhere.
  • Shoulders of Doom: Just look at them.
  • Slave to PR: Played with. He is legitimately as nice, helpful and kind as his subjects make him to be. Unfortunately, he is not as hyped with breaking the barrier and bring "humanity's destruction" as his subjects are and want him to be.
  • Stepford Smiler: Everyone knows him as a cheerful, friendly guy, and his diary in New Home has him note what a lovely day it is, but the fact of the matter is that the loss of his family has left him a sad, broken man who just wishes that this tragedy would come to an end.
  • Stout Strength: He is capable of single-handedly swinging around a big honking trident taller than himself, and certainly does not look particularly slim.
  • Suicide by Cop: He is the only character in the game who you outright tell they can't kill you for good no matter how many times they try, as your death resets the timeline. Logically, this would be a way to spare him: what's the point of fighting you if there's only one possible eventual outcome? The only obvious answer is that he's trying to get you to kill him. In the second and further Neutral endings, if you spare him, he outright commits suicide to let you leave...
  • Talking the Monster to Death: Averted: he's one of two opponents you face in the Neutral or Pacifist route who must be defeated by force; however, talking to him with the ACT command will hurt his will to fight, reducing his attack and defense, as will eating Toriel's pie.
  • Totalitarian Utilitarian: Asgore genuinely believes his plan will make the monsters happy. Though he views it as a matter of necessity, believing that there's no other way.
  • Tragic Villain: He clearly hates himself for attempting to take the human child's soul and probably didn't want to kill the six humans either, but still felt like he had to do it to give the other monsters hope.
  • Villain with Good Publicity: With all the NPCs saying things about how nice he is, the player probably thinks he's this. Then you meet him and... he actually is as nice as they say. Played with a bit in how the story introduces him. When characters refer to him as the antagonist, he's initially referred to as Asgore. When characters refer to him as the lovable king, he's referred to as King Dreemurr. It isn't until Undyne states his full name where it's made explicit that they're both the same character. From that point on, Asgore and Dreemurr are used interchangeably.
  • Violence Is the Only Option: Invoked. On a Pacifist or Neutral run, he begins his fight with you by smashing the MERCY button, and trying to talk to him won't do any good.
  • Voice Grunting: He has a deep voice... and it gets deeper when you face him.
  • Well-Intentioned Extremist: Asgore takes it a step further by wanting to clear the surface so that monsters can live there alone peacefully.
  • Willfully Weak:
    • According to Undyne, he is perfectly capable of dodging attacks, yet he chooses to remain stationary and tank attacks like every other monster does. According to his examine text, he's got the second-highest attack and defense stats in the game, sharing this place with Toriel. According to everyone from Toriel to Mettaton, he is capable of putting you into the ground the moment combat begins. Out of shame, he refrains... which serves as a Drama-Preserving Handicap in favour of the player.
  • Would Hurt a Child: Asgore will kill any humans he discovered no matter how old they are and intends to kill the one the player controls, but still, very clearly despises himself for doing it.

Minibosses

Napstablook

oh, i'm REAL funny.

sorry... i just made this more awkward... pretend you beat me... oooooooooo

A very downbeat ghost that hangs on the Ruins. He actually lives in Waterfall, where he manages the family snail farm. He is also a music aficionado and a DJ.

Tropes exhibited by this character include:
  • Achievements in Ignorance: In the Pacifist route, he manages to avoid being absorbed by the final boss by merely closing his windows, shutting the blinds and not answering the door.
  • all lowercase letters: He talks this way.
  • Apologetic Attacker: Napstablook inverts this trope, as he apologizes for not attacking you, due to him "really not feeling up to it right now."
  • Bedsheet Ghost
  • Big Damn Heroes: Napstablook comes in to break up the stalemate between you and the Mad Dummy... if only by complete accident. Later on, he calls to Mettaton inadvertently convinces him that you shouldn't be killed.
  • Catching Some Zs: Napstablook repeatedly says "z" over and over to make you leave him alone. It doesn't work. The characters do all genuinely go "zzzz" when they sleep though. The joke is that in Napstablook's case, the textbox actually spells out that the ghost literally is saying "z" instead of acting believably asleep.
  • The Eeyore: Unless the protagonist makes an effort to cheer him up. And even then, it doesn't last long. He's generally in an endless downer mood, to the point his favorite activity after meals is to just flop on the floor and feel like trash for hours.
  • Foreshadowing: Minor example during his fight, should you try to kill him, notice how he doesn't flinch upon taking an attack. Continue to attack, and he reveals that ghosts can't be killed that way, and he was only lowering his HP to be polite.
  • Headphones Equal Isolation: Big blocky ones.
  • Hidden Depths: If the protagonist flirts with Napstablook in response to his "Dapper blook" trick, his only response is "oh no...", implying that either Napstablook thought his attempt to amuse the human child went a little too well, or that he's slightly uncomfortable with being flirted with.
  • Leitmotif: "Ghost Fight", which later gets downplayed into "Pathetic House" when you meet up with him again later.
  • Mini Boss: He blocks the player's progress forward, and engaging him in battle is the only way to get past. Unless you're on the Genocide route in which case, he'll immediately disappear.
  • Nice Guy: A bit overly-passive and gets in your way briefly, but all in all, he's very friendly and inviting. And when you try to kill him, even though you can't? He lowers his HP on purpose just to be polite.
  • Nice Hat: He cries himself one, a tiny little top hat made of his own tears. He calls it the "Dapper blook".
  • Nigh Invulnerability: Because he's incorporeal, he can only ever be harmed because he lowers his own health bar in order to be polite.
  • Punny Name:
    • While he's first encountered pretending to sleep on the ground, his name also sounds like Napster, an old file sharing program. He's later revealed to be a DJ who uses another file sharing program to download music.
    • Napstablook also sounds a lot like "naps to block", which is exactly what he does in the Ruins.
  • Shrinking Violet: Napstablook is quiet, shy, socially awkward and overly polite.
  • Skippable Boss: If you're going for the Genocide run, one of the required encounters will just vanish. Napstablook fades away as you approach his sleeping spot.
  • Spanner in the Works: When Mad Dummy realizes you can't hurt it, and it can't hurt you, it decides to keep you in the fight forever by refusing do anything during its turn. Napstablook unknowingly halts the battle by coming in to say hi and driving Mad Dummy away with his tears.
  • Swiss Army Tears: He can both attack and form clothing with his tears.
  • Turns Red: If you don't cheer him up or flirt with him after he displays his "Dapper blook", his attacks get absolutely brutal and borderline undodgeable.
  • Villain Forgot to Level Grind: He's exactly the same on Hard Mode as he is in a normal game despite almost everything else being stronger. Apparently, he "missed the memo and is the same difficulty as normal", as CHECK tells you.
  • Warmup Boss: Napstablook is the first enemy in the game whose attack patterns are legitimately hard to dodge even if you know what you're doing... but the pacifist way to beat him is very obvious, and if you do it right, he'll only actually attack you for one round (being scripted not to attack on the second round of the fight or the turn before it ends). Also, he's a lesson about how bosses are harder to spare than enemies are, while still being unkillable so you don't mess up a Pacifist run against them if you can't figure it out; no other boss except the Mad Dummy lets you off easy like that.

Doggo

Did something move? Was it my imagination? If something WAS moving... For example, a human... I'll make sure it NEVER moves again!

A sentry dog that has the amazing power of seeing things that move.

Tropes exhibited by this character include:
  • Angry Guard Dog: The image he evokes.
  • Dark Is Not Evil: Doggo looks like a typical gangster with wacky clothing and knives as his signature weapon. He's just as friendly as the other dog-type monsters. It's been speculated that he only dresses up like that because his reverse motion blindness (can only see moving things) makes him unaware of what he's wearing.
  • Dogs Are Dumb: Doggo is smarter, but his inability to see unmoving things hampers him, and he thinks the former two dogs are much smarter than they actually are.
  • Gameplay and Story Integration: Doggo's inability to notice stuff that isn't moving is reflected in his blue attacks, which cannot harm a stationary player. If the player does get hit by them, they got noticed, and he uses regular white attacks.
  • Gratuitous Japanese: When you pet Doggo, the word WAN floats around him as he freaks out. 'Wan' is the Japanese onomatopoeia for a dog's barking.
  • Knife Nut: Fond of knives, judging for his sprite and attacks.
  • Leaning on the Fourth Wall: Doggo can't see things that aren't moving. If you try to talk to him, he gets jumpy and asks "Who's there?!". He can't see who's talking to him... because you can't move during dialogue.
  • Living Motion Detector: Doggo can only see things that are moving, a point very much stressed in the early-game to teach you about blue attacks.
  • No Smoking: Played for Laughs (considering smoking occurs elsewhere in the game), Doggo has a fondness for smoking dog treats, of all things.
  • Not So Stoic: Doggo seems pretty serious when you first meet him... and then you pet him, and anything that made him imposing vanishes.
  • Oh Crap: Doggo has this reaction when he's pet by something he's inferred to not exist (or at least not see).
  • Punny Name: "Doggo" is somewhat archaic slang meaning "to remain motionless and quiet to escape detection" (i.e. exactly what you need to do when facing Doggo).
  • Real Men Wear Pink: Doggo, the most threatening of the dogs in appearance, wears a pink shirt with a dog face on it.
  • Rummage Sale Reject: In contrast with his squadmates (who wear armor or cloaks), Doggo wears a ridiculous outfit of a pink sleeveless shirt with a dog face on it and leopard-print pants. Fans tend to agree that his inability to see still objects causes him to wear things like this.
  • The Stoner: Near his station, there are several smoked dog treats.
  • Warmup Boss: Doggo teaches you about light blue attacks that don't hurt you if you stand still: if you didn't encounter a Vegetoid in the Ruins, this is the first non-white bullet you'll see.
  • Weaksauce Weakness: Doggo can't hurt you if you hold still.
  • What Kind of Lame Power Is Heart, Anyway?: Doggo is really good at sensing motion. And that's literally the only thing he can see, so anyone standing perfectly still is completely invisible to him (and this is reflected in his attacks, which are all of the blue variety and can be avoided by standing still).

Dogamy and Dogaressa

A dog marriage

What's that smell? (Where's that smell?)
If you're a smell... (... identify yoursmellf!)

A married couple of dogs that are sentries in Snowdin Forest. They can only identify enemies by their smell.

Tropes exhibited by these characters include:
  • An Axe to Grind: They wield giant axes that have eyes on them. They slam them down for one of their attacks.
  • Battle Couple: Dogamy and Dogaressa are married.
  • Dogs Are Dumb: They seem to be the smartest overall, but even they aren't too complicated, allowing you to fool them into thinking that you're some kind of puppy if you roll around in the snow.
  • Evil-Detecting Dog: They have great noses when it comes to smelling for potential human intruders, which is why they attack you in the first place. Fortunately, wallowing in the dirt will get rid of the human scent and help when sparing them.
  • Happily Married: One of the battle comments is that they are "saying sickeningly sweet things to each other."
  • Heroic BSOD: Killing Dogaressa will cause Dogamy to become depressed, and his attacks become completely impotent. On the flipside, Dogaressa slips into an Unstoppable Rage and gets even more powerful if Dogamy dies.
  • Leitmotif: "Dogbass" plays as the Dogi investigate the area, just before they attack.
  • The Nose Knows: They depend almost entirely on their sense of smell to identify intruders. A crucial part of sparing them involves rolling around to disguise your scent.
  • Roaring Rampage of Revenge: If Dogamy is killed before Dogaressa, Dogaressa flips out and becomes much more relentless in her attacks.
  • Sickeningly Sweethearts: The Dogi are said to call each other overly cute names during battle.
  • Spell My Name with a "The": In-battle text refers to the female of the Dogi as "the Dogaressa".
  • Tertiary Sexual Characteristics: Dogamy has Big Ol' Eyebrows and a pseudo-mustache, while Dogaressa has long eyelashes. They're nearly identical otherwise.
  • Warmup Boss: They teach you that certain ACT commands change in response to other ACT commands and thus you'll have to do this sequentially to get to them to back down.

Greater Dog

Just a big puppy

Another dog sentry in Snowdin Forest.

Tropes exhibited by this character include:
  • Animated Armor: Or maybe a Mini-Mecha. The big, hulking Greater Dog is actually a normal-sized dog riding a massive suit of armor.
  • Big Friendly Dog: Greater Dog looks gigantic and intimidating, but all he wants is some TLC, and will gladly leave you alone when he gets some.
  • Canis Major: He first appears like a Precious Puppy hiding in a snow poff. Then the rest of him and his armors gets out...
  • Gentle Giant: The Greater Dog is described as such when spoken about in Grillby's, and if played with and petted is more than content to lie down in the child's lap... while wearing his hulking suit of armor.
  • Go Fetch: An important part of sparing him.
  • Leitmotif: The Greater Dog has "Dogsong" playing during his encounter.
  • Screw This, I'm Outta Here: If you ignore Greater Dog for several turns, he will leave out of boredom.
  • Stealth Pun: One of Greater Dog's attacks is a tiny sleeping dog. If you move at all, you'll wake the dog and cause it to attack. Let sleeping dogs lie.
  • Top-Heavy Guy: Greater Dog, whose chest and arms are gigantic compared to his positively tiny head and legs. Except that he's actually just a regular-sized dog in some sort of pilotable armor.
  • Vocal Dissonance: The Greater Dog has a very deep bark, which is fitting for the kind of person who would normally wear armor as big as he does, but not for the average-sized dog he actually is. Unusually, this goes both ways, in that Greater Dog introduces himself from his snow poff by sticking his head and tail out, then giving a couple of high-pitched, yappy barks, which makes him seem cute... until he reveals that he somehow hid his entire massive body underneath the snow. This makes him seem like a squeaky-voiced titan instead.
  • Warmup Boss: Greater Dog combines all of the attacks, using light blue bullets, having ACT commands that change in response to previous ACT commands, and requiring the same ACT to be used multiple times to spare him.
  • Weapons Grade Vocabulary: One of the Greater Dog's attacks is a tiny sleeping dog that, if woken up by moving, will send damaging "BARK"s at your SOUL.

Glyde

"Refuses to give more details about its statistics."

A secret boss found in a cave in Snowland forest. He is really rude and pretentious.

Tropes exhibited by this character include:
  • Attention Whore: Worse than Ice Cap, even. To spare him, you have to deliberately deny his attention after giving him some.
  • Bonus Boss: Considering he's as much an Easter Egg as he is an actual enemy, defeating Glyde isn't acknowledged in any way besides the money you obtain.
  • Boss in Mooks Clothing: Doesn't have a unique battle theme and doesn't take that long to defeat, but he's effectively invincible, deals a lot more damage than anything else in the area, and is difficult to find on your own.
  • Eyes Do Not Belong There: His "defeated" sprite reveals that the spot on his tail is a third eye.
  • Guide Dang It: To fight him, you have to find his cave, stay in from of the door, and keep moving for a long of time in game, with the minimum amount being 3 minutes and increasing if the player have killed more monsters. No hint in the game about all of this
  • Jerkass
  • Secret Character
  • Totally Radical: He weaponizes this trope, thanks to his attack explosions turning into "cool" words.
  • Weapons Grade Vocabulary: His larger projectiles explode into words like "Nicey" and "Chill".

Mad Dummy

Foolish. Foolish! FOOLISH!

A extremely irascible training dummy the player finds in the Garbage Dump in Waterfall.

Tropes exhibited by this character include:
  • Bad Boss: He is very rude to his underlings, firing them when the player avoids their attacks.
  • Belly Mouth: Instead of a stitched seam, he has a jaw of teeth below his midsection.
  • Chekhov's Gunman: He's the cousin of the Training Dummy in the Ruins, and his reason for attacking you relates to how you handled the fight with him.
  • Deadly Dodging: You can only hurt him with his own bullets, which come from other dummies that he summons.
  • Death by Irony: He spends the whole fight trying to kill you out of revenge for how you treated his cousin, sort of. In the Genocide route, he's so furious at your terrible personality that the raw anger causes his spirit to bond with the dummy, making him corporeal and perfectly killable for the first time.
  • Disproportionate Retribution: His reason for trying to attack you if you wasted time until the Training Dummy flew away? You're really boring, and boring people don't deserve to live.
  • Evil Laugh: When he realizes that you can't harm him, and he can't beat you, he laughs at the prospect of keeping you stuck in battle forever.
  • Hair-Trigger Temper: No matter what the player does when examining him, he will take offense and attack.
  • Jerkass: He pretends he's attacking you to avenge his cousin, but that's just an excuse. Really, he just wants the player character's soul for his own selfish ends. He never shows remorse for it either. Even on the Genocide run, he's immediately okay with you and lets you go once he gets what he wanted, and his supposed rage at your murderous actions disappears completely.
  • Knife Nut: He will try to knife you. Fortunately, he has only one knife.
  • Laughing Mad: Naturally. He truly breaks into this after his last attack, cackling loudly to the point that his separate pieces start to fly apart out of a combination of anger and borderline craziness.
  • Leitmotif: "Dummy!", a remix of "Ghost Fight".
  • Mathematician's Answer: The 1.001 update changes his CHECK description so that instead of a numerical value, his defense is simply listed as "YES".
  • Mean Boss: To say that he's upset at his mini-dummies for accidentally shooting him is putting it lightly. He fires all of them mid-battle because he's sick of getting shot by them.
  • Mecha-Mooks: He will eventually dismiss the regular bullet dummies for hitting him instead of you, causing him to replace them with robotic dummies that fire homing projectiles instead (they're not much better though).
  • Mini Boss: Has more pomp and circumstance than a regular enemy, but doesn't have an effect on the overall plot.
  • Misguided Missile: In his second phase, the missiles his dummies fire must be redirected so they can hit the Mad Dummy. These missiles stop tracking you after a few seconds and continue flying off; this is required to hit him because the missiles usually don't leave the range of your SOUL's movement.
  • Nigh Invulnerability: Being a ghost possessing a dummy, he is immune to physical attacks. Subverted in a Genocide run, where he manages to become one with the dummy through sheer anger, thus making him corporeal enough to hit.
  • No Sell: Hit him with your own attack, and he'll just rebuild itself, no worse for wear.
  • Puzzle Boss: He's immune to physical attacks (since he's a ghost) and refuses to back down and let you spare him. The only way to progress is to trick him into hitting himself with his own magic projectiles.
  • Rule of Three: He tends to repeat his words three times before he makes any progress. This even drips into his song (a remix of Napstablook's theme) which constantly repeats chords three times before continuing on with the song.
  • Screw This, I'm Outta Here:
    • Finally decides he's had enough when Napstablook cries his magic tears on him.
    • In a Genocide run, the Glad Dummy will make the same kind of exit as the standard Dummy if you fool around too much. This is one of the less obvious ways to cancel a Genocide run without resetting.
  • Suddenly Shouting: His speech pattern goes from normally voiced, louder and finally ALL IN CAPS.
  • Surrounded by Idiots: His mini-dummies that shoot magic attacks. After he takes too many of them, he gets angry(er) and fires them in a huff.
  • Tactical Suicide Boss: His attacks are the only reason he can be hurt. To his credit, he realizes this and changes up his attacks twice in an attempt to avert it. However, all of his good attacks are the ones he can be hurt by; the one that can't hurt him (the knife) only has one shot, and the battle ends after he throws the knife.
  • Verbal Tic: Repeating himself three times, each getting progressively louder, is his Verbal Tic. Even referenced in his battle theme where certain lines play three times before carrying on with the rest of the song.

Royal Guards

A pair of very close bros

Bummer. This is, like... Mega embarrassing. We, like, actually totally have to kill you and stuff.

Two royal guards, a rabbit and a dragon, send by Undyne to catch the human. They attempt to do that deed in Hotland. They also seem to like each other romantically.

Tropes exhibited by these characters include:

Muffet

"If she invites you to her parlor, excuse yourself."

Ahuhuhuhu... You think your taste is too refined for our pastries, don't you, deary? Ahuhuhu... I disagree with that notion. I think your taste... Is exactly what this next batch needs!

A female spider monster who runs a shop, selling baked goods. She has a low opinion of humans because she heard that they like to step on them or their their legs off and also are very stingy with their money. She was actually hired to off you. Once you manage to spare her, she is actually quite nice.

Tropes exhibited by this character include:
  • Achilles' Heel: Gameplay-wise, she can be defeated in the first turn if you eat a spider-based food item in front of her, thus proving that you care about her cause!
  • All Webbed Up: Her special soul effect, which turns your soul purple. You're confined to hopping between horizontal tracks rather than floating freely like normal.
  • Anthropomorphic Food: Has a "pet" muffin monster that attempts to eat the player's SOUL, chasing them upwards in a Rise to the Challenge scenario.
  • Arachnid Appearance and Attire: Muffet has a five-eyed, spider-like face and a total of 8 limbs. Most of her attacks involve spiders.
  • Bad Boss: Downplayed: making her spider friends into pastries is one thing, but feeding them to her pet cupcake monster while trying to attack you is another. The spiders don't mind though.
  • Battle Boomerang: One of her projectiles acts like this, with it flying almost entirely across one of the lines before flying backwards. Going with the food theme, they're actually croissants.
  • Blue and Orange Morality: Even if you're in the Genocide route, and she's perfectly aware that you're a violent psychopath, she's perfectly willing to let you go when she finds out that you've never harmed any spiders. There's also the fact that she has it out for you in any route because she thinks you hate spiders, but bakes spiders into her own pastries.
  • Bribing Your Way to Victory: You can pay Muffet some of your money to have her reduce her attack power on any turn. This price goes up every time the option is taken. Alternatively, you can avoid fighting her by buying food from her, or by eating something you bought from an earlier spider bake sale.
  • Calling Your Attacks: After each turn, a small, normal spider will walk on screen holding a sign with pictures of donuts, croissants, spiders or a cupcake, indicating what type of attack Muffet will use next.
  • Cute Little Fangs: Muffet sports a pair that always protrude from her mouth.
  • Cute Monster Girl: You have to admit, she does look adorable in her little outfit and matching tea sets. Though, considering that female spiders eat their mate...
  • Edible Ammunition: In addition to sending spiders out, she'll toss in donuts and croissants when attacking. Considering her own Carnivore Confusion, the spiders themselves also count as this.
  • Elegant Gothic Lolita: Her looks and dress evokes it.
  • Giggling Villain: "Ufufu~".
  • Hold the Line: In order to spare her, you need to last long enough for a spider to come along with a telegram for her saying that you haven't hurt any spiders. You can skip right to the note by eating something you bought from the bake sale back in the Ruins.
  • Hypocrite: She attacks you because she believes you kill spiders. You know, those same spiders she makes her pastries out of? Of course, her anger towards you seems more directed at you being cruel to spiders and torturing them rather than simply killing them to eat them like she does.
    • Hypocritical Humor: Whenever someone refuses to buy her wares, she considers them to be "greedy". Meanwhile, she's incredibly greedy herself. Probably subverted: if you kill her, you can get whatever money you spent bribing her back, in a way that implies that she was not as greedy as appeared.
  • Leitmotif: "Spider Dance", which is partially a remix of "Ghost Fight".
  • Made From Real Girl Scouts: All of the products of her spider bake sale are made with real spiders. She also intends on using the protagonist as an ingredient.
  • Meaningful Name: Her name is an obvious reference to the "Little Miss Muffet" poem, in which a spider frightens away a young child.
  • Mini Boss: You must fight her in order to move forward, and her battle is rather unique and hard, but she has no impact on the narrative, and you can even skip the whole battle if you do the right thing.
  • Money Fetish: You can pay her money in battle to reduce her attack power, and the ways to skip fighting her both involve spending money. Also, she was hired by someone for a lot of money to take the player's SOUL.
  • Nice Job Breaking It, Hero: Letting her ramble on a Genocide run reveals Alphys personally warned her about you during the evacuation, and left an escape path leading to the capital. Upon using said path, the Hotland would seal up behind her and trap you inside. Unfortunately for Alphys, Muffet refused to abandon her nest and completely shrugs off the evacuation, preferring to kill you herself. As a result, you simply murder her and move on through the Hotland unimpeded.
  • Noblewoman's Laugh: "Ahuhuhuhu".
  • Pet Monstrosity: A giant, cupcake-like spider monster that has an intense appetite? Perfect pet for someone like Muffet.
  • Pinball Projectile: If she angles her donut projectiles, they'll bounce off the walls of the dodge window.
  • Psycho for Hire: She was offered a lot of money to take the protagonist's SOUL.
  • Rise to the Challenge: Her cupcake monster acts as this: it chases your SOUL upwards across several lines for quite a while. The wall is the easy part in this case; the hard part is the mass of spiders that are being sent down to the monster while you're trying to climb upwards.
  • Signature Laugh: "Ahuhuhuhu~".
  • Skewed Priorities: During a Genocide run, she knows and acknowledges that you are a bloodthirsty mass-murderer. She's still perfectly willing to spare you though, simply because despite all the people you've killed, you still never harmed any spiders among them.
  • Spiders Are Scary: At least, when you don't buy their baked goods. Subverted for the most part, as she's pleasant otherwise.
  • Spontaneous Choreography: Two text boxes that display at the beginning of your turn note that the spiders are clapping to the music, and that Muffet eventually joins them in a synchronized dance.
  • The Tease: She'll offer some rather suggestive lines if you opt to stay in her web after she decides to spare you, and tells you that you're free to come back and let her tie you up any time.
  • To Serve Man: She initially intends on using the protagonist as ingredients in her pastries, but grumps that they don't look very tasty.
  • Vague Age: Her creator described her as "a lil' baby spider monster", but clarified that it wasn't literal. She's seen running her own business, and she addresses the protagonist as "deary".
  • Well Intentioned Extremist: She needs money for the purpose of raising funds to rescue the spiders trapped in the Ruins, as they cannot make it past Snowdin's cold weather.

So Sorry

An optional boss. He is a very timid artist, attempting to make an "art club". He can be found in a secret room in Hotland, on a certain day and date.

Tropes exhibited by this character include:
  • Adorkable: A clumsy, nervous, constantly-apologizing artist that's constantly Shy Finger-Twiddling, and is a cute, chubby, floppy-eared dragon wearing a vest and a bowler hat.
  • Apologetic Attacker: He's not even trying to attack you; his "attacks" are just being generally clumsy in his attempts to draw you a picture, with a tail strike or tossing paper around. As if his name wasn't a more obvious indication.
  • Apologises a Lot: It's in his name, even.
  • Art Attacker: All his bullets have the shape of scribbles, and it's implied that are his drawings coming to life in bullet form.
  • Art Initiates Life: He's an artist with a magic pencil, but accidentally draws some monsters that come to life in an attempt to draw a picture of you.
  • Author Avatar: Of one of the Kickstarter backers.
  • Bonus Boss: So Sorry (yes, that's his name) is very obscure to find. There's a hidden path in Hotland near Sans's hot dog stand. The encounter still doesn't trigger unless all of the elevator stops are available and the internal clock is set to October 10, 8:00pm.
  • The Cameo: One of several characters added to the game by a Kickstarter backer.
  • Fixed Damage Attack: Inverted. All your attacks do exactly 1/11 of his HP.
  • Flunky Boss: He'll accidentally summon a few crudely drawn monsters partway through the fight, though they can be sent away easily.
  • Guide Dang It: Reaching So Sorry requires having your computer's time set to a very specific setting and going through the secret path that opens up in a specific place. It is very unlikely to have this happen by accident. If you manage to find the room during the Genocide route while fulfilling the conditions to encounter him, instead of him, you will find a note saying "Art club have been suspended."
  • His Name Really Is "Barkeep": One of the first things he says when encountering the player is "I'm so sorry!". He is So Sorry.
  • Holiday Mode: Fighting him at all also requires a specific date and time.
  • Leitmotif: "Wrong Enemy !?".
  • Motor Mouth: Noticeably during the fight, his text prints much faster than any other character in the game.
  • Mundanger: See Apologetic Attacker above.
  • Secret Character

Supporting Characters

Monster Kid

Hey, don't tell my parents I'm here. Ha ha.

A young monster who lives in Snowdin Town. They idolizes Undyne, leader of the royal guard, and temporarily travels with the player, hoping to see Undyne (who is currently tracking down the player).

Tropes exhibited by this character include:
  • Accidental Hero: Thoughout the human child's trip through Waterfall, the Monster Kid frequently saves the human child from getting caught or killed by Undyne just by being at the right place at the right time.
  • Ambiguous Gender: Their gender is never stated in the game, since no opportunity for it to be revealed in a sentence ever occurs. The Japanese official translation has them use "ore", so this points that they is a boy... maybe.
  • Armless Biped: Appears to be this, they often trip but pull themselves back up without the use of arms or any other kind of appendage, and if you don't pick up an umbrella during the rainy segment in the Waterfall, they remark that it seems that you can't hold one either. Their tarot card also shows them running through Snowdin holding a popsicle in their mouth.
  • Break the Cutie: Several ways of doing this. when they nearly falls of a bridge during the Neutral or Pacifist route, you can choose not to help them, which causes Monster Kid to lose trust in humans. Meanwhile in the Genocide route, you can attempt to attack Monster Kid. While Undyne takes the blow, Monster Kid runs away, terrified.
  • Character Shilling: They do this with Undyne, telling the player how cool and awesome and righteous she is constantly as you walk through Waterfall. Though it turns out to be true, the player may not initially agree since Undyne is trying to kill them at the time.
  • Chekhov's Gag: After every encounter, they will trip as they run off, to the extent where it becomes a Running Gag. This turns out to set up for them to fall off a bridge, barely hanging on to the edge near the end of the Waterfall. They survive because even if you choose not to help, Undyne will rescue them.
  • Comically Missing the Point: It takes them a remarkably long time to figure out that you are a human.
  • Go Through Me: If you save them on a Neutral/Pacifist run, they stand between you and Undyne and shakily states this trope word for word. On the Genocide run, they stand in your way because they won't allow you to hurt anyone else.
  • Hero Worshipper: They admire Undyne greatly, and traverse Waterfall for a chance of meet her. At the end of the game, they shift their admiration towards Papyrus.
  • The Klutz: They frequently trip and fall on their face, presumably because they don't have arms. In their tarot card artwork, they have a bandage on their head.
  • Look Behind You!: If you've already seen their speech on the Genocide run, this is how it is shortened on future attempts; they start their speech but they turn around and say "What? Look over here? What for—" before the game goes to the battle screen for the Undyne fight.
  • Nice Job Breaking It, Hero: In a Genocide run, they follow you around while Undyne is hunting you, and at a few instances, Undyne gives up on a chance to slay you so as to remove them from the area for their own safety. If you complete a Genocide run, then it's partially because the Monster Kid got in the way.
  • Running Gag: Literally! When they break out into a run, before leaving the frame, they'll trip and fall flat on their face before getting right back up and continuing their run.
  • Shoo the Dog: When they finally figure out you're a human, they ask you to be mean to them so they can feel okay about hating you, since your races are enemies. If you refuse, they'll reluctantly insult you instead. If you choose to insult them, they laugh saying that their sister calls them that all the time, so they have to insult you instead anyway.
  • Verbal Tic: "Yo!".

Nice Cream Guy

Tell your friends... There's ice cream... Hidden in the depths of a watery cavern...

A rabbit trying to boost his Nice Cream business. Has a tendency to set his stall in very inappropriate places, and moves thorough the Underland searching for clients.

Tropes exhibited by this character include:
  • Amazing Technicolor Population: He's a blue rabbit-like creature.
  • Break the Cutie: If you don't spare a mandatory encounter by killing the monsters involved, he will remain upset and hopeless about his business, since said encounter had the monsters buy all of his Nice Cream if they were spared.
  • Cannot Tell a Joke: According to Burgerpants, he thinks that the nice messages on his Nice Cream wrappers count as jokes.
  • The Ditz: Believes that an cold, snowy area is the perfect location for enjoying ice cream.
  • Dungeon Shop: His first two locations are located in the middle of Snowdin and Waterfall. The one at Hotland is past the point enemies spawn, so it doesn't count.
  • Everyone Calls Him "Barkeep": The only character that mentions him in dialogue simply calls him "the Nice Cream guy".
  • Foil: A cheerful guy despite his business failures, in contrast with Burgerpants, who is successful but loathes his job.
  • Intrepid Merchant: He seems to be following the same trail as you, though this means that he sets up shop in the worst places possible.
  • Nice Guy: To a point where it rubs off onto his products. It makes up most of his name.
  • No Name Given: Never gives out his name, and nobody else mentions it.
  • Odd Friendship: With Burgerpants. Apparently, Burgerpants can't stand the Nice Cream Guy's lack of a sense of humor, but puts up with it because he gets free food out of it.
  • The Pollyanna: No matter how business goes, he's always willing to keep going. The only thing that can stop him is killing the Royal Guards.
  • Recurring Traveller: Appears in three different locations throughout the game to sell his wares.
  • Stepford Smiler: While he's definitely optimistic and shows a lot of emotion when he has a customer, it's easy to see how upset he is at his lack of success. Should you kill the Royal Guards, he'll drop the act entirely and become rather gloomy.
  • Throw the Dog a Bone: In addition to him being overjoyed when you buy his Nice Cream, sparing the Royal Guards will cause them to buy out his entire stock, encouraging him to stay in business.
  • Took a Shortcut: No matter how fast you go, he'll always be able to make it from mid-Snowdin to mid-Waterfall before you. Same thing goes for mid-Waterfall to the end of Hotland, though at least in this case, the "shortcut" in question could be the elevator system.
  • Visual Pun: There's an American brand of ice cream called Blue Bunny.
  • You Are Better Than You Think You Are: The messages on the Nice Cream wrappers (that display when used) are very uplifting.

Snowdin Shopkeeper

Hiya! Welcome to Snowdin! I can't remember the last time I saw a fresh face around here.

The bunny who manages the general store in Snowdin.

Tropes exhibited by this character include:

Gerson

A very cool old monster

Studying history sure is easy when you've lived through so much of it yourself!

A former hero who retired and now has an store in Waterfall. Has a lot of knowledge about the local lore and embarrassing anecdotes of the King and the local heroine.

Tropes exhibited by this character include:
  • Adventurer Archaeologist: Certainly looks the part despite his age, with his magnifying glass and pith helmet. However, the only artifacts he has on sale are actually the equipment of the purple SOUL, or at least copies of them.
  • The Atoner: Implied. Despite having been a war hero, he says that "I'm no hero, never was" implying some guilt over something he did during that time.
  • Cool Old Guy: He's pretty friendly and playful (assuming you're not in a Genocide run at least), if only a bit senile.
  • Deadpan Snarker: On a Genocide run, he falls firmly into this. Quotes include "So you came... what a treat!" and "Don't expect a discount".
  • Lampshade Hanging: If you try selling him anything, he'll point out how ridiculous that'd be, since he doesn't want MORE junk on his hands.
  • Long Lived: He actually fought in the first Human-Monster war millennia ago.
  • Medium Awareness: On the Genocide route, he implies that he knows you can't attack shopkeepers, and is happy to charge you money and chat with you to buy more time for other monsters to evacuate.
  • Mr. Exposition: If you ask him about the Delta Rune and its significance. Notably, he's the only one who refers to the symbol by name.
  • Rambling Old Man Monologue: Some of the stuff he says has this vibe.
  • Retired Badass: Was once a hero much like Undyne is now. He was apparently called the Hammer of Justice. Though if you call Undyne outside of his shop, she mentions he's a legend for having been in the war because he survived it, not because he did anything special during it, which speaks leagues for how horrifically one-sided the war truly was.
  • Seen It All: His age helped a lot in his knowledge of history, since he's lived through most of it.
  • Shop Keeper
  • Signature Laugh: "Wa ha ha!".
  • Time Abyss: He's old enough to have been in the human/monster war.
  • Turtle Power: Definitely a turtle; for "power", see Retired Badass above.

The River Person

Tra la la. Why don't you sing with me. Tra la la.

A hooded person who provides both transportation between locations and cryptic messages that can or can not have hidden meanings.

Tropes exhibited by this character include:
  • Ambiguous Gender: "I am the riverman. Or am I the riverwoman...? It doesn't really matter."
  • Black Cloak: Their emblematic outfit.
  • Catch Phrase: "Tra la la..."
  • Cool Boat: It's normally a bland piece of wood, but occasionally and randomly, it will turn into a dog-headed boat that moves by levitating and running over the water.
  • Cryptic Conversation
  • Dark Is Not Evil: Wears a black hooded cloak and their face (if any) is covered entirely in shadow, yet they're simply another friendly and sociable monster... one who serves as public transportation, at that.
  • Don't Fear the Reaper: They look like the Grim Reaper with the mysterious hooded cloak, but they're pretty personable and helpful, all things considered.
  • Expy: Their character seems to be a Shout-Out to Kapp'n from Animal Crossing, as a wise boat-master who imparts random tidbits of trivia in song. Also resembles Charon, the ferryman of the river Styx in Greek Mythology.
  • The Faceless: Their face is obscured by a hood.
  • The Ferry Man: Fits perfectly the classical depiction of this trope, being a hooded figure who allows the player to travel from place to place using their boat.
  • In the Hood: They always wear their hood up, which contributes to how mysterious they are.
  • Nerves of Steel: They're the only character that the Fallen Child directly interacts with during a Genocide playthrough who doesn't react to them in the slightest despite everything that's happening around them, even though they don't have the innate protection against being attacked that shopkeepers like Gerson and Burgerpants do. Maybe the protection extends to all fast travel services as well?
  • Verbal Tic: Tends to begin their speeches with "Tra la la".


Temmies

RATED TEM OUTTA TEM.

hOI!!!!! i'm tEMMIE!!!!

Weird catdog creatures that live in a hidden town in the Waterfalls. Some of them appear as enemies in the map before their town.

Tropes exhibited by these characters include:
  • Author Avatar: Of the game's primary artist Temmie Chang. In the credits, while most characters are listed as being created by someone, Temmie is credited as being Temmie (the artist) as opposed to being made by her.
  • Broke the Rating Scale: After a patch in January 2016, using CHECK on Temmie will state her ATK and DEF are "Tem outta Tem".
  • Catch Phrase: "hOI!! i'm temmie".
  • Cloudcuckoolander: All of tem. They're easily some of the strangest monsters in the game. Their faces seem to be completely separate from their bodies, allowing them to move around the front of their head freely and even completely separate if you wait long enough when you're in battle with one of them, and if you pay the Tem Shop shopkeeper's college fee, she leaves her face behind while the rest of her moves offscreen.
  • Creator Cameo: Temmie is one of the artists who contributed to the game.
  • Cute Kitten: A part-cat, part-dog monster that's all adorable.
  • Cuteness Overload: They love humans. Unfortunately, humans (or at the very least, the protagonist) are allergic to Temmie. One of their attacks when you encounter them is a stretching paw that gently touches your SOUL before retreating (which is to say, attacking by petting).
  • Cuteness Proximity: For humans. They go absolutely ballistic if they find you, gushing over how cute you are.
  • Department of Redundancy Department: Her Golden Ending title is... "Temmie". Both white and yellow titles, in fact.
  • The Ditz:
    • A whole species of them. For instance, one of them is trying to hatch an egg, which upon examination turns out to be hard-boiled.
    • The Tem Shop shopkeeper is also the only shopkeeper you can sell items to, on the basis of just having poor impulse control. If you keep selling her items, she randomly decides that she wants to buy that specific item at a higher price while simultaneously complaining that she should save money for college instead, but she never actually runs out of money to buy your items: as a result, you can fund her college solely by buying items from her and selling them back to her, implying that she already had all the money she needed to go to college, but was too stupid to realize it.
    • Encountering Temmies in battle can result in them forgetting their own attacks, or accidentally misspelling their name in the battle screen (as "Temmiy").
  • Enemy Summoner: Flexing at them during a battle will cause Aaron to appear, and Temmie to run away.
  • Expy:
    • They're quite similar to the Mr. Saturns from EarthBound with their strange speech patterns, nonsensical village and alien demeanor along with a verbal tic in their dialogue.
    • Also possibly to Nepeta of Homestuck as Aaron is to Equius, given the unique interaction they can have.
  • Genki Girl: If you encounter them in battle, they're constantly vibrating in place.
  • Humans Are Special: Temmies LOVE humans and find them to be cute.
  • Karl Marx Hates Your Guts: Hilariously inverted. The Tem Shop shopkeeper seems to have no concept of the value of money... she'll pay much more for some items than other items which are much stronger, and you can sell her own items back to her (or items sold by the nearby shopkeeper Gerson) for a higher price than you paid for them.
  • Leitmotif: "Temmie Village" and "Tem Shop", which are remixes of "Dogsong".
  • Muscle Angst: Flex in front of one, and she'll remark "NO!!!!! muscles r... NOT CUTE"... Then Aaron will pop up, and Temmie will simply run off because she can't stand him and his muscles.
  • Odd Name Out: They're all named Temmie. Except for Bob (who also is the only one who speaks standard English).
  • OOC Is Serious Business: Played for laughs with the Tem Shop shopkeeper if you refuse to sell her something that she's offering you extra money for.
  • Out of Character Alert: If the Tem Shop shopkeeper is refused on her offers to buy stuff, she will become deathly serious and talk in standard English instead of the whimsical way Temmies usually talk.
  • Painting the Medium: Their dialogue is filled with bizarre spelling, capitalization, and punctuation errors that Funetik Aksent alone can't account for.
  • Planet of Hats/Planet of Steves: Almost all Temmies are named Temmie and their hat is Cloudcuckoolandery.
  • Plot Allergy: The Human is allergic to Temmies, and one Temmie is also allergic to humans, getting "hOIVS" on contact.
  • Puff of Logic: The Temmie that is allergic to itself doesn't show any signs of a reaction until it tells you as much, then it immediately breaks out in "hOIVS".
  • Ridiculously Cute Critter: Just see tem!
  • Rubber Man: Their attacks consist of stretching their limbs to either 'pet' you or walk around with the chance you'll bump into their legs.
  • Self-Deprecation: For artist Temmie Chang. She was put in the game... as an entire species of complete idiots.
  • Shout Out: To the Mr. Saturn in EarthBound.
  • Spell My Name with an "S": The correct spelling is "Temmie", but "Temy" and "Temmiy" also pop up due to weirdness (the former being the spelling used for the Temmie Armor, the latter occasionally popping up in battle flavor text). "Tem" as shorthand seems to be consistent, at least.
  • Trademark Favorite Food: Temmie Flakes. Which are made out of construction paper.
  • Ultimate Blacksmith: Paying for the Tem Shop shopkeeper to go to college will allow her to create for you the single best armor in the game. It starts out ridiculously expensive, but the price goes down every time you die.
  • Uplifted Animal: One Temmie in the village, who goes by the name of Bob and speaks in an intelligent manner.
  • Verbal Tic: A few of the words in their dialogue are puns of the word "hoi" ("bOI!", "hOIVS!")
  • Voice Grunting: A cat-like chattering noise.
  • We Buy Anything: The Tem Shop shopkeeper will buy anything from you, including items that she just sold to you a few moments ago, and often at a higher price than you bought it for.

Bratty and Catty

Your standard alley girls

I'm Bratty, and this is my best friend, Catty.
I'm Catty, and this is my best friend, Bratty.

An alligator and a cat that manage an store in the alley besides MTT Resort. They sell stupidly expensive stuff (albeit not as overpriced as the resort food).

Tropes exhibited by these characters include:
  • Big Sister Worship: Towards Alphys, of all people.
  • Childhood Friends: They were friends with Alphys when they were younger, though Alphys is enough older than them that they describe her as a "big sister". However, they haven't hung out with her in awhile, since Alphys is now the Royal Scientist.
  • Cute Little Fangs: Catty has them. Well, she is a cat.
  • The Dividual: For all matter, they are one girl in two bodies. They are so similarly minded that most of their speeches are basically the same idea with sightly different wording, when they are not Finishing Each Other's Sentences or Finish Dialogue in Unison, making the few times they have different opinions very striking.
  • Fan Girls: Of Mettaton, to the point that Catty tries to pay you to get Mettaton to sign her butt. They also both go off on a long spiel about being married to him, where he just doesn't know it yet.
  • Fat and Skinny: Implied in their their shop sprites. Catty's the fat, while Bratty's skinny.
  • Fell Off the Back of a Truck: The vibe their store gives.
  • Heterosexual Life Partners: Despite both loving Mettaton, Catty offhandedly mentions "[she] doesn't want to have a dream without [Bratty] in it."
  • Like Is, Like, a Comma: To go with their Valley Girl accents.
  • Meaningful Name: Bratty and Catty are Exactly What It Says on the Tin.
  • Multicolored Hair: Catty's hair is black with dyed blue bangs.
  • Non-Mammalian Hair: Bratty, an alligator monster, has blonde hair styled in Regal Ringlets.
  • Ship Tease: With each other, but Catty also mentions that though Burgerpants is weird, she also thinks he's "kind of cute".
  • Shop Keeper
  • Signature Laugh: MEOW-MEOW! Incidentally, this is the cat sound from the music composition game in Mario Paint.
  • Skewed Priorities: On the Genocide path, the two leave a lengthy note with both of their own comments to the protagonist insulting them and telling them not to take their stuff... because they didn't want their pens to go to waste. And all the while, Alphys was trying to get them to evacuate.
  • Stealth Pun: Together they are an Alley-cat and an Alley-gator. They are also V-alley girls.
  • Trademark Favorite Food: Glamburgers. If you choose the "sell" option, they ask you to get them some, and they get excited if they notice that you are carrying one.
  • Valley Girl: Extremely so.

Burgerpants

I'm getting on in years, so let me give you some advice, little buddy. You've still got time. Don't live like me. I'm 19 years old and I've already wasted my entire life.

The neurotic beleaguered teenager managing the MTT Burger stand in MTT Resort. Extremely frustrated with the lack of direction his life has taken.

Tropes exhibited by this character include:
  • Affectionate Nickname: If the player gets friendly with him, he'll regularly call them "Little Buddy". Inversely, if the player is doing the Genocide route, he'll call them "Little Weirdo".
  • Be Careful What You Wish For: He used to actually want to work with Metatton. Now he does, and he couldn't be unhappier. He even quotes the name of the trope word for word.
  • Broken Pedestal: He used to be a fan of Mettaton before actually working for him.
  • Burger Fool
  • Cartoon Creature: He looks like a mix between a cat and a bear, and due to his constantly changing sprite, sometimes he looks more like one than the other.
  • Cigarette of Anxiety: He regularly lights up a cigarette when talking to the player, no doubt to relieve the stress of his job.
  • The Cynic: Completely resigned to being stuck in his terrible job forever, thinks friendship is just a way for attractive people to enslave you, generally has nothing good to say about anything or anyone... He has a bad case of it. The only thing that keeps him going is the hope that the barrier is broken and that he can leave the fast food business behind him to pursue his acting career.
  • Embarrassing Nickname: And it's the only name he's ever called. He is called "Burgerpants" because of an incident where he tried to smuggle burgers to impress Bratty and Catty, but was discovered by Mettaton when the burgers he has hidden made his pants drop down.
  • Expressive Accessory: The M on his hat changes along with his sprite. Sometimes it's an M, sometimes it's a squiggle, and sometimes it's a W.
  • I Ate What?: According to him, Glamburgers are at least partially made out of (edible) sequins and glue.
  • Looking for Love In All the Wrong Places: He seriously considers accepting a date with the Alley Girls despite knowing that they only want him for the free stuff and attempting to impress them had caused him humiliation in the past.
  • Non-Standard Character Design: He wouldn't look out of place in an episode of Ren and Stimpy. His face, and the rest of his body for that matter, don't stick to one shape between his different expressions.
  • Off-Model: Invoked. All of his expressions are radically different.
  • Only Known by Their Nickname: And an embarrassing one to boot. He got stuck with it after an attempt at smuggling some Glamburgers for Bratty and Catty got him startled by Mettaton, and his pants dropped when trying to pick up some burgers that fell out, which caused all the other burgers in his pants to spill out.
  • Playing a Tree: The credits show him as a bush in a play Mettaton is performing.
  • Small Name, Big Ego: He fancies himself a jaded worldly person with the potential to be a great actor. Really, he's just an insufferable lazy cynic that often blames others for his problems. He tends to go on trying to impart wisdom to you about how the only way to get through life is to lie to yourself, and that attractive people only ever want to take from you. You can convince Catty and Bratty to invite him on an outing to the dump, mostly out of pity.
  • Stepford Smiler: Almost all of his expressions have a smile of some sort, but for his dialogue, it's obvious that's it is him trying to keep a professional smile.
  • Suspiciously Specific Denial: In the Genocide route, he's aware that the protagonist is killing everyone, but he continues his job as if nothing is wrong, even when questioned about everyone leaving.
  • Vague Age: The only character in the game who averts it. He specifically claims to be 19 years old.

Spoiler Characters

These characters, while referred to in the Neutral route, have most of their information revealed in the Pacifist and Genocide routes, when not hidden in the game code. They are Walking Spoilers. Thread carefully.

The Fallen Child

A long time ago, a human fell into the RUINS. Injured by its fall, the human called out for help.

A human who, long ago, fell into the underground. They were adopted by the Dreemurrs, bud sadly died of a terrible illness, and his death and failed attempt to return his body to the surface was the Start of Darkness for the Underground in general. In the Pacifist route, it's revealed that their death was actually death by self-inflicted poisoning, and they actually tried to pull a self-sacrificing Thanatos Gambit in a half baked plot to destroy first the barrier, then mankind as an act of vengeance against what they did to monsters. Their attempts to do so, by fusing their soul with his adoptive brother, failed spectacularly, and they died not much after, but not permanently. In the Genocide route, he is awaken by the player actions, and is thoroughly disgusted/entranced by them.

They are probably the most enigmatic character in the game, with several theories and camps of interpretation. For a long time they were semi-unanimously considered the actual Big Bad of the game (due to their appearance and choice of words near the end of the Genocide route), but after several fans pointed out instances of them not being as bloodthirsty maniac as originally thought (particularly the notorious essay that popularized the notion that they may be the game's narrator), the general opinion towards them nowadays tends to be more benevolent, or at least Depending on the fanartist.

Tropes exhibited by this character include:
  • Abstract Apotheosis: They are the embodiment of RPG stats. On one hand, the Fallen Child becomes the embodiment of killing everything to gain power in the Genocide route; in order to achieve 100% Completion, you have to do some pretty horrible things, including kill every single friend you've made in a previous run. On the other hand, the Fallen's stats help protect Frisk in the Pacifist route.
  • Ambiguous Gender: Like the player character, their gender isn't actually specified and is referred by "them" pronouns.
  • And I Must Scream: In the Genocide route, and possibly in the other routes, the Fallen Child now remains stuck as a voice in Frisk's head. However, after completing the Genocide route, they can completely take Frisk's soul.
  • Anti-Anti-Christ: One interpretation has the Fallen Child once being evil, but then turning good through the Pacifist route, supplying Frisk the final memory to save Asriel.
  • The Antichrist: It is said that the Fallen's presence brought much hope to the Underground. If the Fallen Child is interpreted as Evil All Along, they are this. Otherwise, they may be an Anti-Hero.
  • The Atoner: The "Narrator Fallen Child" theory would make them this in the Pacifist route. After being responsible for the death of their brother, the breakup of their parents, and Asgore declaring war on humanity, all by trying to kill people to save the Underground, now they're going to use Frisk to save everyone by not killing everyone. Averted in the Genocide route.
  • Audience Surrogate: It's strongly implied that, on some level, they're supposed to be a representation of the player or some kind of vessel for the player's intentions. Exactly how far this goes is up for debate. Notably, you give them a name of your choice at the beginning of the game and you're encouraged via Word of God to give them your name (if you can't think of anything else... naming the Fallen Child after your cat is also permitted).
  • Badass Adorable: Should it ever come to it, that cute little kid with the rosy cheeks and the sweet smile can easily destroy your entire world, take your SOUL, and use your body to murder everyone you love.
  • Badass Bookworm: Assuming the Fallen Child is the narrator at all times, at one point (when helping the Royal Guards), the text "I see two lovers staring over the edge of the cauldron of hell" shows up, which is a reference to semi-obscure Japanese novel Kitchen by Banana Yoshimoto.
  • The Bad Guy Wins: If you go through with getting the Genocide ending, the first human wins. Forever. Even on subsequent playthroughs... well, that is until a player erases all records of their corruption, but details, details.
    • Or do they? Did they actually want to destroy everyone they loved? Did they even love anyone in the first place? It all depends on your viewpoint.
  • Best Served Cold: According to some, the Fallen's hatred for humans unfortunately outweighed their love for their adopted family, and that Asriel's betrayal and the Fallen Child's mummification was a catalyst for this murder spree.
  • Big Bad: For the Genocide route, and worst of all, it's your fault if they win.
  • Big Bad Duumvirate: Seemingly with Flowey of the Genocide route, until it turns out Flowey is also on their hitlist as well...
  • Big Brother Bully: Implied by the True Lab's tapes, where they pressure a reluctant Asriel into helping with their suicidal barrier shattering plan, with Asriel's dialogue implying that Fallen Child is guilt-tripping him into complying.
    • This is taken to the extreme during the end of a Genocide run, where the player character viciously stabs a scared and pleading Flowey to death, so hellbent on their goal that they think nothing of butchering what's left of their brother figure. If you take the theory that the Fallen Child has taken over the player character at this point, it's an obvious act of revenge for his perceived betrayal.
  • Big Good: If interpreted as the narrator or player, they are this for the Pacifist route.
  • Blood Knight: In the Genocide route, the exclamation mark will be replaced with a smiley. To wit, after you've killed every random encounter in an area, the Fallen Child will attempt to engage in a fight with empty space. Repeatedly.
  • Blush Sticker: Has a permanent rosy blush to their cheeks.
  • Body Surf: The Fallen Child and Asriel planned to unseal the barrier by having Asriel take their soul, going up, and taking six more souls. Asriel backed out halfway through, killing them both. In the Genocide route (or all routes, according to some fan theories), the Fallen Child now resides in Frisk.
  • Broken Bird: Sympathetic portrayals tend to be this. Even if they aren't or never were evil, it's obvious that the Fallen Child was/is seriously messed up.
  • But Thou Must!: Choosing to not erase the world has the Fallen Child tell you that you're not in control, then does it anyway. Selecting the option on any subsequent Genocide playthrough has the Fallen Child say that "you made your choice long ago", and still do it.
  • Came Back Strong: If they are the narrator of the Pacifist route, then they are kinder and wiser than they were implied to be in life, and help Frisk SAVE Asriel and break the barrier.
  • Care Bear Stare: For the Pacifist route, if they are believed to be the narrator or player. They may have hated humanity, but even though it would only take the monsters getting Frisk's soul for Asgore to unseal the barrier and declare war, they aid Frisk in saving everyone, monsters and humans, without a single person getting hurt.
  • The Corruptible: If one subscribes to the "Narrator Fallen Child" theory, then it seems like that they were turned into an Omnicidal Maniac by the Anomaly's influence.
  • Creepy Child: Even before they emerge in a Genocide route, it was clear that there was something off about this kid from the start. After all, not many kids concoct a freedom plan that involve killing themselves as the main step.
  • Creepy Monotone: The further you go down the Genocide route, the more monotone the narration becomes. By the final cutscene, the Fallen Child speaks in a deadpan tone, without Voice Grunting and in mostly short sentences.
  • Dark and Troubled Past: Asriel implies that the Fallen Child had good reason to run away from home.
  • The Dark Side: Becomes increasingly corrupt with the more EXP and LV you gain.
  • Death Seeker: Implied in the backstory. They climbed Mt. Ebott, where people are said never to return from, for reasons that weren't "very happy", according to Asriel.
  • Decoy Protagonist: After a fashion in the Pacifist and Neutral runs. The opening of the game, along with the subsequent naming sequence, lead the player to believe that the Fallen Child is the character they're playing as. It's not until the end of the Pacifist run that it's made clear that the player character is Frisk. In a Genocide run, they're a straight-up Villain Protagonist.
  • Diabolus Ex Nihilo: Along with Frisk, little is known about the Fallen Child's reason to visit Mt. Ebott, their life before the underground, or why they have a hatred for humanity.
  • Didn't See That Coming: The Fallen Child assumed correctly that Asriel would absorb their soul after they died, gain untold power that the Fallen Child would take control of, and easily slay humanity. They didn't realize that Asriel still maintained some control, though. With Asriel holding the Fallen Child back, they end up sustaining mortal injuries from the human mob.
  • Dissonant Serenity: Once the Fallen Child introduces themselves, they look the same as Frisk but with their eyes wide open and a hearty smile instead. That gentle facade will fall apart if you try to defy them though.
  • The Dog Bites Back: One interpretation of the Fallen Child turning against you in the Genocide ending and hijacking your Pacifist endings. After all, you made them destroy everything and everyone they cared about. Of course, their vengence would mean doing just that killing everyone they love over and over just to spite the player.
  • The Dreaded: There are no townspeople in the Genocide route; the NPCs have all evacuated and hid in a shelter somewhere, not stopping to clean out their money drawers. Doggo shivers when Frisk approaches him.
  • Driven to Suicide: Along with their method of monster liberation, this is highly implied to be the reason they climbed the mountain in the first place. Their fall may have been accidental, but their presence in the mountain definitively was not.
  • Emotion Eater: One interpretation is if Asriel became soulless when he attaches to a flower, the Fallen Child might have done the same with Frisk. According to Asriel, he can only feel the feelings of the soul he's attached to, so it would also explain why the Fallen Child's emotions reflect Frisk's actions: the Fallen Child's narration grows warmer over the course of the Pacifist route, while it grows colder over the Genocide route.
  • Enemy Without: In the Genocide ending, they break free of listening to you and start doing their own bloodthirsty thing, so that they can keep killing and destroying forever.
  • Enfant Terrible: Regardless of their Ambiguously Evil status prior to death, there's no doubt whatsoever at the end of a Genocide route that they've become one of the most evil children in video game history: a complete and total Omnicidal Maniac, utterly devoid of any empathy or compassion.
  • Even Evil Has Loved Ones: Probably, anyway. While they were still human, they seemed to have some measure of love for Asriel and his family, although Asriel makes it clear at the end of the Pacifist route that their relationship still wasn't healthy. There's even evidence that this affection carries over into the Genocide route, although it doesn't stop them from hacking Asriel to bits once you nudge them into it.
  • Evil Counterpart: To Sans. Both are the very snarky sibling (or step sibling in the Fallen Child's case) of an innocent loving sibling, both like puns and are almost always smiling, and both have a Mysterious Past. But the Fallen Child ends up killing Asriel, something Sans would NEVER do, and the Fallen Child's smile is meant to show there Dissonant Serenity over there crimes. Also symbolically, Sans is a sort of metaphor for the game (being quirky and simple on the outside, but complex and mysterious on the inside) while the Fallen Child is a metaphor for the player.
    • Could also be considered one to Mettaton. The Fallen Child is a human who hated humans and wanted to cross the barrier to wipe them out, Mettaton is a monster who came to love humans, and wanted to cross the barrier to STOP the war. Both also have subtle biblical references in there characterization: Mettaton's name is a reference to Metatron, an angel of life, while the Fallen Child has allusions to Lucifer.
  • Eviler Than Thou: By the end of a Genocide playthrough, even Flowey is terrified of them, and is eventually reduced to begging to be spared. Should you feel remorse and refuse to destroy the world, they'll point out you don't have any say in the matter and prevent you from playing the game.
  • Evil Has a Bad Sense of Humor:
    • In the Genocide route, Sans is even alarmed when they fail to respond to any of his initial jokes. He then attempts to hide them behind the conveniently-shaped lamp, but an impatient Fallen Child walks past it.
    • "That comedian..." The "comedian" in question is Snowdrake. If Snowdrake is not dead before the counter is exhausted, the SAVE point text will change to "The comedian got away. Failure", and the Genocide route will be aborted. Boy, tough crowd.
    • What few jokes the Fallen Child does make in this route lean toward the tasteless side. Upon being inspected, the hole in the laboratory wall will yield the message "It's just here to complete the look."
    • They will describe the bag of dog food as "half-empty" (as opposed to "half-full"), followed by the message "You just remembered something funny." This message appears after killing Lesser Dog, Greater Dog and Doggo.
  • Evil Laugh: From the Tainted Pacifist ending. If you choose to stay with Toriel. It's even more horrible than Photoshop Flowey's! You can also hear the traces of one in their jumpscare if you choose not to destroy the world in the Genocide's conclusion.
  • Exact Words: The name entry screen asks you to "name the fallen human". It never said which fallen human. The child being "fallen" can also refer both to the child having fallen into the Underground, fallen as in "died", or "fallen from grace".
  • Exposition Fairy: Acts as this for most (if not all) of the Genocide run. The Narrator Fallen Child theory posits that they are this in Neutral and Pacifist runs as well.
  • The Faceless: Has their face hidden in the intro and in Asriel's flashbacks. It's only in the Genocide route when we see their face.
  • Face of an Angel, Mind of a Demon: At the end of a Genocide run, their rosy dimples and sunny smile run entirely counter to the kind of creature they actually are at that point.
  • The Fourth Wall Will Not Protect You: Want to go back and reset after the Genocide route? Bad news: the Fallen Child destroys the game. Literally. The final thing the Fallen Child attacks is the game itself.
  • The Grinch: In the Genocide route, inspecting the Christmas tree at the center of town displays the message "Nothing for you". The protagonist can also take three snowman pieces from the Snowman until he becomes a "useless pile of snow".
  • Heel Face Turn: One way to interpret their character arc, if one believes they were villainous in life but redeem themselves in the Pacifist route.
  • Hello, Insert Name Here: They are the character you are actually naming in the beginning. In fanworks, they are usually called "Chara", as it was the the placeholder name used in promotional screenshots, and if you introduce it in the actual naming screen in the game, it gives the message "The true name". At some point, Toby Fox said that, if you couldn't think of a name to use, you should use your own.
  • Hidden Villain: Despite being the catalyst of the Dreemurr family's breakup, Asgore's declaration of war against humanity, and Asriel's death then revival as the wicked Flowey, none of the characters save for the player, Flowey/Asriel, and possibly Sans ever uncover or know of the First Child's impact on these events by any ending, including the Golden Ending. Although, the Easter Egg on the naming screen where you can attempt to name the First Child after the main characters may prove otherwise if such is canon.
  • Humanoid Abomination: The Fallen Child's actions through Frisk in the Genocide route cause several monsters to wonder if they're human, or even a monster. Also worth noting is that within the game's canon, a human cannot absorb a human soul just as a monster cannot absorb a monster soul, yet the Fallen Child can still take Frisk's soul after the Genocide route...
  • Humans Are the Real Monsters: Apparently, the Fallen Child believed this, and given what he attempted to do, they actually skirted this trope.
  • Hypocrite: They say the player has a "sick sense of morality" for doing the Genocide route twice, and yet no matter how many times you replay the Pacifist route, the Fallen Child will always hijack it and kill everyone.
  • Identical Stranger: The reason Flowey confuses Frisk for the Fallen Child is because they look almost identical in appearance and even "fashion sense".
  • I Know Your True Name: When attempting to name the Fallen Child "Chara", the response becomes "The true name".
  • Interactive Narrator: If they really are the narrator, they're this trope to previously unheard of extents, starting with them being able to tell the player about different monsters by checking them and the player being able to affect and corrupt the Fallen Child by killing monsters, making the narrative itself change and reflect your choices and actions, and finally ending with them subjecting you to the horrifying narrative tone you gave the story in the Genocide run.
  • Interspecies Adoption: Adopted by the Dreemurr family, a family of monsters, after falling into the Underground.
  • Jerk with a Heart of Gold: If they did genuinely care about Asriel and/or wanted to free the monsters. They were willing to hatch up a plan that would involve killing people, and are implied to act in a very harsh and manipulative manner to get Asriel to go along with it, but they meant well. If they're interpreted as the narrator, they're also this way to Frisk in their sarcastic comments. However...
  • Jerk with a Heart of Jerk: If they didn't care about the Dreemurr family or the monster race, then they're this.
  • The Killer in Me: The Villain Protagonist of the Genocide route: a crazed killer whom the lesser monsters fear and the more powerful ones die fighting heroically.
  • Knight Templar: Is implied that they did these terrible things as an act of vengeance against humans (similar to Asgore), even though in the process they may have ended up destroying the monster world as well.
  • Lack of Empathy: It's implied that, like Flowey, the Fallen Child has no soul and literally cannot feel any emotion.
  • Lemony Narrator: If one believes that they narrate the Pacifist and Neutral routes. They regularly tease and joke with the player character, make sarcastic comments about the scenery, and rename the items into funny abbreviations during battles (e.g. Butterscotch-Cinnamon Pie becomes "ButtsPie").
  • Look Behind You!: If you die to Undyne the Undying and try again, the Fallen Child uses this on the Monster Kid to get him to drop his guard quicker.
  • Manipulative Bastard: The video tapes you find in the true lab make it pretty clear they regularly took advantage of Asriel's trust and naivete, egging him into their murder-suicide plan even though he wasn't comfortable with it.
  • Meaningful Name: The semi-official placeholder name used for the Fallen Child, "Chara", isn't only a shortened form for "Character", but has several meanings in other languages (included, but not limited to, "dear/friend", "joy", "empty" and "punishment"), and also is the name of a star in the Canes Venatici constellation. Because of this, many people believe that a Dummied Out song titled "Star" was going to be their leitmotif.
  • Menacing Stroll: A few characters notice the way the Fallen Child walks is unsettling. Papyrus calls it shambling.
  • Metaphorically True: You are asked to name the "Fallen Child" at the beginning of the story, giving you the impression the game meant the player character, when it really meant the Fallen Child.
  • Misanthrope Supreme: They developed a hatred of their home village and humanity before arriving in the Underground, and are more than willing to kill at least a few humans in exchange for getting out with Asriel. How many targets they really had, and whether it was for the monsters' sake or for their own vengeance, is up to the player's interpretation.
  • Mission Control: In the Genocide route, they advise Frisk that Sans can't keep dodging and to just keep attacking. They might also be this in Neutral and Pacifist runs.
  • Mission Control Is Off Its Meds: Played straight in the Genocide route, even telling the player that Monster Kid is just free EXP.
  • My Death Is Just the Beginning: The First Child convinced Asriel to go along with a plan to poison them, so that Asriel could absorb their soul, and the two could pass through the barrier, allowing them to take the souls of six additional humans to open the barrier. This plan fails when Asriel gets cold feet and resists the First Child's attempt to attack the humans at the village they arrive in.
  • My Rules Are Not Your Rules: Manages to pull this on both Sans and the player during the last Genocide boss fight. Throughout the fight, both you and Sans understandably expect the FIGHT command to initiate one attack per turn. But after Sans dodges your attack yet again after using his "special attack", the Fallen Child retaliates on their own with a second unprompted attack.
  • Mysterious Past: Although it's been said that the Fallen Child's reason for traveling to Mt Ebott was because they hated humanity. Though exactly what made them hate other humans is unknown.
  • Nice Job Breaking It, Hero: In their first and only appearance, the Fallen Child reveals that the protagonist's "human soul" and "determination" were the cause of their reincarnation and that the bloody events that transpired over the course of Undertale lead the Fallen Child to realize that the purpose of their awakening was power itself.
  • Not So Different: Their deeds are all one massive reflection of the player themselves in the Genocide route because YOU are the one who decided to start killing monsters en masse.
  • Omnicidal Maniac: The Fallen Child seems to grow stronger based on how murderous the player's actions are, ultimately culminating in the Fallen Child taking over and destroying the game itself.
  • Pay Evil Unto Evil: One interpretation from the endings of the SOUL-less True Pacifist route is, that the Fallen Child reminds the Anomaly, that they are "not above consequences". It still remains questionable, if they did indeed kill everyone on the photo or if it was a elaborate prank on the Anomaly.
  • Player Character: Either a subversion or double subversion, depending on how you view the Fallen Child: are they the main villain, the narrator, or are you controlling the human because you are the Fallen Child?
  • Poisonous Friend:
    • The Fallen Child pressured Asriel into a plan that would ultimately involve murdering humans no matter what. It backfired, killing them both. The Fallen Child may continue to be this on the Genocide route towards Frisk. Reversed in the Pacifist route, maybe.
    • This is expressly stated by Asriel if, after completing a Pacifist run, the player walks all the way back to the first screen to talk to him. Asriel will admit that the Fallen Child probably wasn't the greatest person, and he shouldn't have so readily trusted them.
  • Reaching Between the Lines: The 9999999999999999 was the WORLD being hit, hence the screen shuddering on 'impact'.
  • Reality Warper: The Fallen Child has the ability to completely erase or to recreate reality. An interesting example because the Fallen Child is strongly suggested to be an in-game representation of a typical RPG player (possibly the player), who can of course delete a game or reinstall it on their computer.
  • Rewarded as a Traitor Deserves: After Flowey kills his father (after trying to warn him of you), he tries to make himself seem useful so you won't kill him. He gets hacked to pieces for his trouble. Try to back out your run at the last second, and they'll kill you too.
  • Sanity Slippage: Some theories suggest that the progressive effects of EXP and LV corrupt the Fallen Child from a benign force, to a being Driven to Suicide and at the end of the spectrum into an Omnicidal Maniac.
  • Screw This, I'm Outta Here: The Fallen Child's narration is completely absent during the Omega Flowey fight, aside from "You called for help", and exclaiming that Flowey's defense has dropped to zero when the souls finally help you out. This is justified though in that, while the Fallen Child likely lived long enough in the Underground to know the strengths and weaknesses of each monster, Omega Flowey is a complete Eldritch Abomination that the Fallen Child has never seen before. The narration is also oddly absent during the Toriel and Asgore bosses, frequently becoming simply Visible Silence.
  • Sealed Evil in a Can: Some fans believe that after they're "awakened" at the beginning of the game, they're powerless to actually do anything unless you "feed" them enough EXP to fully come back from the dead. Some fans believe this corrupts them, turning them from good to evil, while others believe they're either biding their time or too weak to fully express their true personality during non-Genocide routes, making them a very abstract example of this trope.
  • Secret Test of Character: One of the theories about the Fallen Child is that they're keeping an eye on the Human to see if humanity is still as messed-up as they remember.
  • Self-Sacrifice Scheme/Thanatos Gambit: Their plan to free the monsters involved committing suicide via buttercup poisoning (a very unpleasant way to die) and let their soul being taken by Asriel.
  • Sesquipedalian Loquaciousness: Their dialogue at the end of the Genocide run demonstrates a few cases of this (for instance, saying 'eradicate' instead of 'kill') coupled with a Creepy Monotone. The Neutral/Pacifist narration shows similar diction as well.
  • Shadow Archetype: While their actual morality is ambiguous, they have shadowy and demonic themes going on to contrast with Asriel's angelic ones. To begin with, they are an entity that if you summon can only be stopped by selling your soul to them. Also, their origins vaguely parallel Luzbel/Lucifer: they're stated to be the first human to fall into the underground, just like Lucifer is often seen as the first angel created by God and the first who rebelled against Him; they're described as having been believed to be an angel or savior (the "future of human and monsters"); and it's shown that their death was caused by their hatred of humanity, just like Lucifer's fall was inspired by hatred/jealousy of human beings. To followers of the "Evil Fallen Child" theory, they're a voice in the back of the hero's head pretending to be heroic and helpful, very similar on how several religions depicts demonic temptation. There is a reason even the kindest fan depictions deliberately contrast them with Asriel and play up Frisk apparent morality.
  • Sharing a Body: While the details aren't elaborated on, they probably do something along these lines to Frisk after they fall into the Underground. Whether it's Symbiotic Possession or Demonic Possession depends on which route you walk.
    • They also explicitly pulled this with Asriel in the backstory, during the plan listed above. It didn't go too well.
  • Speak of the Devil: Referenced if you complete a consecutive Genocide run, calling themselves "The demon that comes when it is called."
  • Stepford Snarker/Sad Clown: One of two possible explanations for them "laughing off" the pain, at the time they accidentally poisoned Asgore.
  • Stupid Evil: After killing everyone in the area, the Fallen Child will constantly try to pick fights with the empty space.
  • Super-Powered Evil Side: By the time you reach Undyne in the Genocide route, it's obvious Frisk is not winning all these battles through sheer luck and pluck. There is something more malevolent at work.
  • Talk to the Fist: Beyond what the player does through the Genocide path, the Fallen Child will increasingly walk forward during conversations, engage in fights and strike enemies without any input from the player.
  • Terse Talker: Becomes one in the Genocide route. The save point text being reduced to "X left" and "Determination" is one of the more famous features of the route, but all of the Fallen Child's red text comes across this way.
  • Token Evil Teammate: Might be this to the Human on a Pacifist run.
  • Took a Level in Jerkass: For the Genocide route. They already hated humanity, but now they're out to kill all monsters and eventually reality itself.
  • Took a Level in Kindness: For the Pacifist route, if they are believed to be the narrator or player. They may have hated humanity, but even though it would only take the monsters getting Frisk's soul for Asgore to unseal the barrier and declare war, they aid Frisk in saving everyone, monsters and humans, without a single person getting hurt.
  • Trademark Favorite Food: Chocolate.
  • Tragic Villain: Maybe.
  • Troubling Unchildlike Behavior: It is largely unknown what they were like before their nightmare-inducing soulless Genocide incarnation. However, at five to thirteen years old (like Frisk, their age is ambiguous), they were, at the very least, a misanthrope with a chip on their shoulder for the people of their hometown, not to mention laughing off poisoning Asgore, if only by accident. They planned their own slow agonizing suicide via buttercup poisoning, convinced Asriel to assist with said suicide plan to fuse souls to pass through the barrier, and they were planning to kill at a minimum of six humans in their hometown for their souls. They also had a fixation with knives, with Toriel removing all of them from the house before Frisk's arrival, hinting that the Fallen Child had an affinity for harming themselves and/or others.
  • The Unfought:
    • The only villain of the game that is never really battled. Your only real encounter with them is at the end of the Genocide route, when it's already too late to do anything against them and where they destroy the world.
    • This is a very Justified Trope. If they are the embodiment of your stats, the only way to beat them is to not do the Genocide run. If they are the narrator (and by extention, your Mission Control), you'd essentially be fighting a voice in your head. And if they are you, you'd basically be killing yourself.
  • Ungrateful Bastard: Double Subverted. The Dreemurrs adopted, fed and raised them as their own. Initially, they were presumably grateful, but later ends up killing their adopted father and brother.
  • Vague Age: As with the Human, we don't know how old they were when they fell into the Underground (or how much time has passed since they died, for that matter). They are only described as a child, meaning they could be anywhere between five and twelve years old.
  • Villains Out Shopping: If you believe the narrator theory and that they're also a villain, then the entire Neutral/Pacifist route turns into this, with the Fallen Child powerless to do anything except casually shoot the breeze with you until you decide to kill.
  • Was Once a Man: After their plan with Asriel failed, they're now a soulless entity akin to Flowey, only possessing Frisk instead.
  • Well-Intentioned Extremist: Asriel describes a kid who was hurt in some way by human society, that found a loving family in the most unlikely of places, who was willing to sacrifice their own life to repay this compassion... but ended up screwing things up in the worst way possible. Not the greatest of people, but not the devil either. People on the "Evil Fallen Child" stance believes that whatever well intentions they might have had are gone, at least on the Genocide route.
  • Woobie, Destroyer of Worlds: Possibly, depending on interpretations of their hatred of humanity, and how they fit into the neutral and pacifist routes. Asriel notes their reason to climb Mt. Ebott (where people disappear never to return) wasn't very happy. The "narrator" theory holds it that the genocidal side of the Fallen Child struck when this got sent Up to Eleven.
  • Worthy Opponent: Strongly implied to consider Undyne one, describing her as "the true heroine". Fan work and theories tend to expand on this, having the Fallen Child look up to her on Pacifist runs as well, and drawing explicit parallels between their attitudes towards humanity and her status as the only monster shown to naturally harness Determination.
  • Would Hurt a Child: The opening lines to their "fight" with the Monster Kid in the Genocide route is "In my way". And if you examine them, the description is "Looks like free EXP". Fortunately, Undyne intervenes.
  • Writer on Board: In a Genocide route, the player is implied to both be the Fallen Child and not the Fallen Child at the same time: Schrödinger's little murderer.
  • You Cannot Grasp the True Form: Ultimately, it's not clear what the Fallen Child is in game.
  • Your Soul Is Mine: After killing everyone and destroying the world... it's the very last thing on the Fallen Child's wish-list. And the Fallen Child will get what they want too if you want to replay Undertale ever again after completing the Genocide route. This has profound implications on any further playthroughs you do decide to do.

Asriel

The prince of monsters

Howdy! [Player], are you there? It's me, your best friend!

Asriel Dreemurr was the son of Asgore and his wife Toriel. He was the one who found the Fallen Child, and on time, they were as close as blood siblings. When the Fallen Child died, he took the soul of his recently deceased adopted sibling to bring their body back to the surface, but that ended badly when humans attacked the weird human-monster fusion, forcing them back to the Undergound and die there from the injuries. He was in the known of the Fallen Child plan the whole time, collaborated with it against his better judgement, and he inadvertently caused their death by taking control of their sharing body before harming a human, making them vulnerable to human attacks. He eventually revived as a soulless animated flower, thanks to Alphys' experiments with Determination. The Lack of Empathy he experienced along with the discovery (and abuse) of his resetting powers eventually drove him mad, transforming him into the sociopathic Flowey. In the Pacifist finale, after absorbing the human souls, he absorbs the souls of every monster in the Underground, restoring his original form and then some. He is the final boss in the Pacifist route, having become mad with his newfound power.

Tropes exhibited by this character include:
  • Abnormal Limb Rotation Range: When using his sword attack, he rotates his head 360 degrees, vertically.
  • Amazing Technicolor Battlefield: In his first form, he will wait for the music to swell before turning the background into a trippy rainbow tunnel.
  • Animesque: In the final battle, he crosses the Bishonen Line, calls his attacks, and the attacks themselves are visually stunning and look like complete overkill. It's actually a kind of sad twist on this trope by reminding you that under that almost demonic looking exterior, he's just an preteen fighting like how he would have seen in a cartoon or read in a comic.
  • The Anti-Nihilist: In contrast to Flowey, once redeemed Asriel expresses the opinion that while the world can be a dark place filled with Floweys, what should be strived for is an existence where nobody kills and nobody is killed.
  • Anti-Villain: Really, he is just a child who was betrayed by his adoptive sibling who he still loves and misses. He just doesn't want to be alone anymore.
  • Arm Cannon: One set of his attacks in the first stage of his boss fight has him morph one of his arms into a gun.
  • Berserker Tears: Once you save the souls of all your closest friends from within him, he starts to break down. He'll begin to sob while begging you to let him win, that you and he will be happy together, eventually bursting into a bawling scream as he fires a point-blank Death Ray at Frisk.
  • Bishonen Line: His final boss form is far more powerful than the boss form he assumed as Flowey in the Neutral run, and is also much more anthropomorphic, simply being a grown up version of himself with slightly demonic features. This ends up getting played with a bit upon his second form, which is strange and mechanical-looking, but is still nowhere near the abomination Flowey became.
  • Black Eyes of Evil: In his Bishonen Line form, his sclera are black with narrowed white pupils, contrasting both of his parents who have standard white sclera and black pupils.
  • Boss Subtitles: He's the sole individual who actually has a boss subtitle during his introduction, which makes sense, given that he's a little kid given god-power, and everything he does in this form is his idea of Rule of Cool.
  • Calling Your Attacks: During the first phase of his fight, the text box will announce which attack he'll use. The same attack types even have upgraded versions with different names he uses halfway through. Funnily enough, Asriel isn't actually saying the attacks in his text speech balloons, it's the narrator describing them. This tropes still applies though because it's clear that at least someone is describing them.
  • Came Back Wrong: As Flowey.
  • The Chosen One: In the True Pacifist route, he becomes the Angel spoken of in the Delta Rune's prophecy; he has seen the surface before, having gone there in his attempt to return the Fallen Child's body, and upon returning to his true form and being redeemed he uses his power to shatter the barrier.
  • Clipped-Wing Angel: He's far less aggressive and 'unfair' than Photoshop Flowey, and despite being far more powerful is likely a little easier. This makes perfect sense really, as absorbing all those love filled souls restored his conscience, and he's clearly struggling to sustain the hatred powering his attacks.
  • Crucified Hero Shot: After you save him and get him down to his normal child form, he releases the souls of the monsters and the Fallen Children this way. This also shatters the barrier.
  • Don't You Dare Pity Me!: He refuses to see his parents for a last time, as he knows he couldn't cope with them knowing he will become Flowey again.
  • Even Bad Men Love Their Mamas: His base-power form is borrowed from Toriel's appearance: same height and width, though he wears a tabard with the Delta Rune on it, and has horns that curl outward, as well as the aforementioned Black Eyes of Evil.
  • Even Evil Has Loved Ones: It's the driving force behind his villainy. He simply cannot let go of the Fallen Child.
  • Fallen Hero: In life, he was selfless enough to choose death over murder. After his reincarnation, he'd come to regret his sacrifice and, as a result, adopt a worldview antithetical to it.
  • Fighting From the Inside: Tragically, while this doesn't happen when he's Flowey, when spoken to in the True Pacifist's epilogue, he states that the Fallen Child wanted to use their combined power to annihilate the humans living in their hometown. Asriel resisted, and they were mortally wounded as a result.
  • Final Boss: Of the Pacifist route (and technically the last enemy fought in the other two).
  • Final Exam Boss: Rescuing the Lost Souls involves fighting them in the Red (Toriel and Asgore), Yellow (Dr. Alphys), Green (Undyne) and Blue (Sans and Papyrus) heart modes.
  • A God Am I: His ultimate plan, both as Flowey in the Neutral route, and as his resurrected self in the True Pacifist route. He thinks he and the Fallen Child will become gods in the Genocide route as well. He's wrong.
  • Grand Theft Me: A victim. Asriel absorbs the Fallen Child's soul in the backstory, acquiring a new powerful body, but much to his horror finds out that the Fallen Child also has control over that body and wants to attack the people of their home village with their newfound power. It takes every ounce of willpower to resist the Fallen Child's will.
  • The Greatest Story Never Told: At no point in a Pacifist run (the only run where Asriel can actually come into being) can he be reunited with his parents, or even have the fact he exists again be known to any other character. After he redeems himself, he purposely puts himself out of sight from anyone who knew him, knowing the joy of reuniting with his loved ones would be tragically short-lived, given that he still lacks his own soul and will eventually revert back to a sociopathic flower.
  • Heel Face Turn: Asriel pulls this at the end of the True Ending, having regained his ability to feel compassion (at least temporarily).
  • Heel Realization: Asriel during his boss fight with you, when you reawaken the monster souls he has absorbed, and he starts to regain his compassion. After he turns back into Flowey, he uses this trope as the reason why the player should erase his memories too, should they decide to start a new game... he feels so bad about how terrible he was to everyone around him that he doesn't think he'd be able to play the same role again.
  • Hoist by His Own Petard: Throughout the game, especially in a Pacifist run, he repeatedly exploits the trust and compassion of the people around him in order to get all monster and human souls in one room and devour them simultaneously. When he finally does, he gains the power of a god... but also regains his own compassion, and Frisk's pacifism turns him from a sociopathic maniac to a sobbing wreck who can't bring himself to hurt people anymore. And if you do the True Reset, he points out you're even worse than he is because you're enacting the very same insane, evil plan he was trying to do after even he himself had let it go.
  • Hopeless Boss Fight: Just like when you face him as Flowey, he tries several times to convince Frisk that they are completely helpless. In actuality, Frisk is this for Asriel. No matter what Asriel does, or how many times Frisk is brought down to 0 HP, Frisk's determination keeps them going.
  • I Just Want to Have Friends: The Fallen Child was the closest thing Asriel had to a friend, with the monsters suggesting that Asriel and the Fallen Child were like siblings. Asriel simply cannot let go of his memories of them, to the point of projecting the Fallen Child onto Frisk; he just wants to see his friend/sibling again that badly. This is part of why his Flowey persona is so elated to see the similarities between the two at the start of a Genocide route.
  • Large Ham Title: After the music swells, the "CHECK" command declares Asriel "The Absolute GOD of Hyperdeath!".
  • Leitmotif: "Your Best Friend" and "Memory", which is further reprised in "Undertale" and "His Theme".
  • Living on Borrowed Time: In the Playable Epilogue of the True Pacifist, he's restored to his true form, but says that without a soul, he'll eventually return to being Flowey.
  • Luke, You Are My Father: Odd example. Neither Toriel nor Asgore find out Flowey is Asriel, but Frisk does.
  • Many Spirits Inside of One: His final form, comprised of every soul in the underworld.
  • Meaningful Echo: After you go back to the first screen of the game and talk to him, he'll end the conversation with "Don't you have anything better to do?".
  • Meaningful Name: His name is very similar in convention to angels names, and sounds similar to "Azrael", the angel of death in the Hebrew Bible. His name is also the combination of his parents' names. To round the thing even more, "Asriel" is a real Hebrew name meaning "helped by God", and giving that his resurrection was practically a miracle (i.e. something that cannot happen without direct divine intervention)...
  • Nigh Invulnerable: You cannot harm him in the final battle. Asriel becomes everything the human ancestors feared. Thank goodness, like all monsters, he regains his love and compassion, or else you'd be screwed.
  • No Good Deed Goes Unpunished: All he wanted to do was return the Fallen Child's body to their village out of respect. The humans thought he killed the Fallen Child, and attacked him, leading to his own death.
  • Older Alter Ego: When he fights you, he ages himself up from a child to what looks to be a young adult. He reverts back to his child form once he loses the will to fight, though he briefly assumes his older form again for a gag during the True Pacifist credits.
  • One-Winged Angel: After absorbing the Fallen Child's SOUL, Asriel was stated to have undergone a transformation into a powerful form, which is presumably the same form he takes during the first stage of his boss fight and simply resembles an adult version of his species, similar to his parents. His second form also qualifies, as it resembles a winged, demonic version of himself.
  • Our Angels Are Different: He has a lot of angelic motifs going on him, with his first boss form being "The god of Hyperdeath" (what with his name being very similar to the Angel of Death) having, and his final form has colorful wings.
  • Our Ghosts Are Different: Unlike the Blook family, Asriel is dead and only persists due to having been accidentally revived as Flowey. Once he collects all the SOULs in the Underground, he gains enough power to recreate himself, but chooses to restore everyone instead.
  • Physical God: In his Boss Monster form, he not only has the power of six human SOULs, but of all the other monsters the human child has encountered except Napstablook, making him even more powerful than Photoshop Flowey.
  • Playing with Fire: One of his attacks, shared with both his parents, is a storm of fireballs. Also, like his mother, towards the end of the fight, the fireballs will intentionally start avoiding the player's SOUL.
  • Please Don't Leave Me: Said almost verbatim during the final fight against him on the Pacifist route and combines this with Berserker Tears.
  • Post-Final Boss: After the intense fight with Photoshop Flowey, the Pacifist route's final battle, Asriel Dreemurr, is impossible to lose since you revive each time you die, and you can "dream" for as many healing items as needed. His fight serves less as one final challenge and more as an interactive cutscene which ends the game's story on a high note.
  • Reincarnation: After an unknown length of time passes after his death, Alphys's experiments with determination brought him back to life in Flowey's form.
  • Ridiculously Cute Critter: His child form is this to many fans of the game.
  • Rule of Cool: The form he takes in his first form during his boss battle is this to a T: his attacks and his appearance all incorporate things he really loves: stars, prismatic color schemes and (as mentioned before) his mom. Deep down, he's still just a little boy.
  • Setting Right What Once Went Wrong: His goal.
  • Suicide by Cop: Unintentional, but Asriel purposely held back his power and the Fallen Child's influence when the latter went to attack his hometown. The humans merely saw a monster carrying the Fallen Child's corpse and believed they were avenging him by slaying the monster. Asriel accepted this fate rather than let the Fallen Child annihilate them and possibly kickstart another war.
  • Super-Powered Evil Side: Asriel has no powers by himself, but he is nearly godlike when he is reincarnated as a murderous flower and also when he absorbs the souls of the Underground to become the God of Hyperdeath.
  • Tender Tears: Even admits that he's "a bit of a crybaby."
  • That Man Is Dead: Invokes it on himself to Frisk, claiming Flowey is so different that he's someone else.
  • Thou Shalt Not Kill: Played With. In the past, he refused to kill humans; in the present, while fighting him, he tries while attempting to do an infinite "game" with you, but your soul "refused" and will not die.
  • Time Crash: Seeks to cause one after another using the power of the Six Human SOULs along with every Monster SOUL... locking Frisk in an eternal loop of life with him so he'll never have to let them go.
  • Tragic Villain: He clung desperately to the memory of the Fallen Child, was used as little more than their pawn, and was Forced Into Evil as a result of their influence. He has suffered more than any other character, and despite all of Frisk's determination, you can't save him.
  • True Final Boss: Of the True Pacifist ending, which requires having gotten the Neutral-Pacifist ending. Interestingly, he's both a Climax Boss and a Zero Effort Boss, since you can't lose.
  • Turn Out Like His Father: Inverted. In his powered-up form, he resembles his mother, more than his father.
  • Used to Be a Sweet Kid: Every indication from the story is that Asriel was just as kind as his parents, if not more so. Things quickly went downhill following his friendship with the Fallen Child, the subsequent Demonic Possession, and finally his reconstruction as Flowey without a soul. The betrayal and inability to feel twisted him into something totally unrecognizable from his former self.
  • What Is This Thing You Call Love?: His downfall. After so long being soulless, when Frisk reaches the friends that Asriel absorbed, the feelings of love and compassion monsters have overwhelm him and make him vulnerable to Frisk's SAVEing.
  • Wise Beyond Their Years: Asriel is pretty well-spoken in his child form, probably due to how many times he's reset the world as Flowey; despite not much time actually passing for the world, Asriel/Flowey himself has had a very long time to learn about things beyond his age.
  • Woobie, Destroyer of Worlds: Much less ambiguously than the Human SOULS or the Fallen Child. The worst thing Asriel ever did was take the Fallen Child in and try to be friends with them, and the tapes in Alphys' True Lab indicate that even though he wanted to help the Fallen Child complete their plan out of platonic love for them, he still had his reservations about it, and furthermore, he tried to stop them when it came to fruition. It's because of the Fallen Child's evil that he died, lost everyone close to him, was stripped of his emotions, and gradually turned into what he is when you fight him. So, while his omnicidal actions aren't justified per se, anything he might have been responsible for that brought him to that point was only in the best of intentions, and the greater scope of everything bad that happened wasn't really his fault so much as it was someone else abusing his good will.
  • Yandere: Just like his Flowey persona and for the same reasons, his desire to keep Frisk (who he thinks is the Fallen Child) in the Underground is a platonic variant. Unlike Flowey, however, he grows out of it when he finally comes to his senses.
  • Zero Effort Boss: The True Final Boss Asriel. While his attacks aren't easy to dodge, you automatically revive each time you die, and thus the battle keeps going until you win. While dying can prolong the battle, you ultimately can't lose. And his penultimate attack actively avoids harming you, being the exact same as Toriel's.

The Other Humans
Seven. Seven human souls, and King ASGORE will become a god. Six. That's how many we have collected thus far.
—Undyne

The six humans who fell before the beginning of the game. You can find their possessions (and use them as arms and armor) thorough the game.

Tropes exhibited by these characters include:
  • Ambiguously Evil: One of them (the Blue SOUL) likely killed at least one monster, possibly more, but we have no idea why or how.
  • Big Damn Heroes: After calling out to them enough, they resonate with Frisk and begin turning the fight against Flowey. And when he uses his save state powers to undo his defeat, they unite to utterly destroy him in one shot, saving Frisk from a truly unwinnable situation.
  • Chef of Iron: Implied of the Green SOUL, who used a frying pan as a weapon and wore an apron.
  • Color Coded for Your Convenience: Separately from your Red SOUL and grey monster SOULs; they come in orange, yellow, green, light blue, purple and dark blue. Notably, the colors correspond to the various colors that bosses can turn your SOUL, as well as the three different attack colors.
    • The colors are indicative of the humans' greatest virtue before they died:
      • Light Blue - Patience
      • Orange - Bravery
      • Blue - Integrity
      • Purple - Perseverance
      • Green - Kindness
      • Yellow - Justice
  • Dance Battler: The Blue SOUL was, which explains why ballet shoes are a weapon you can acquire.
  • Empathic Weapon: Even after death, they can still feel emotion and respond to your fight against Flowey.
  • Frying Pan of Doom: The Green SOUL's weapon.
  • Human Sacrifice: They were killed to make someone powerful enough to break the barrier.
  • Improbable Weapon User: Including ballerina shoes, a notebook and a frying pan.
  • Killed Off for Real: They fell in various points during the Underground, it's implied the farthest any of the other souls made it was Hotland (the green and possibly the yellow one, depending on where Catty and Bratty got the Yellow SOUL's equipment from).
  • Knife Nut: The Light Blue SOUL used a toy knife, which can be found in the Ruins.
  • Leitmotif: A different remix of "Your Best Friend" for each of them plays when they are fought during the confrontation with Omega Flowey. Light Blue's and Orange's versions are higher-pitched than the original, Purple's and Yellow's versions are lower-pitched, Blue's uses a whistle instead of chiptune, and Green's uses a piano.
  • Living MacGuffin: Not so much living anymore. Still semiconscious though.
  • Nice Hat: The cowboy hat belonged to the Yellow SOUL.
  • Playing with Fire: Getting past the Green SOUL during Omega Flowey's fight requires dodging waves of flames tossed from three frying pans.
  • Plot Coupon: They're six differently colored (but otherwise identical) objects that are being collected in order to accomplish a goal, which clearly resembles a common type of plot coupon in RPGs. The difference with these? You're not collecting them; the monsters are, and the player character happens to be the last one they need.
  • Posthumous Character: All of them died, and their souls were taken by Asgore before the game began; the exact circumstances of their deaths, either at the hands of Asgore himself or someone else, isn't stated.
  • Power-Up Food: When turned to Frisk's side, the Green SOUL tosses healing bullets shaped like cookies.
  • Rainbow Motif: Together with Frisk's red heart. This also pops up in with 7 coffins with the same color hearts (with the red one being closed), and with Photoshop Flowey cycling through the entire spectrum in his demise.
  • Riddle for the Ages: Why did they climb the mountain and fall into the Underground, what were their personalities like, and how did they die?
  • Ripple-Effect-Proof Memory: Them having this is the only saving grace in the Photoshop Flowey fight. Even if you die, and Flowey reloads, they remember that you've called to them, and they still want to help you. This contributes to them rebelling after you "defeat" Flowey, and he reminds you that he can just reload back to full health.
  • Shout-Out: Much like Frisk's Stick, their weapons, with the exception of the Torn Notebook, belong to classes of MOTHER weapons:
    • Toy Knife: Teddy from the first game had knives as his first two weapons, though these would be outshone by a Sword and Katana.
    • Tough Glove: Kumatora from the third game used gloves.
    • Ballet Shoes: Duster from the third game would kick with his shoes, though none of them were ballet shoes
    • Burnt Pan: Ana and Paula from the first two games fought with frying pans.
    • Empty Gun: Lloyd and Jeff, also from the first two games, wielded guns.
  • We Hardly Knew Ye
  • What Happened to the Mouse?: They're mentioned as missing in the Neutral and True endings, but what happened otherwise is unexplained. Simple logic would state that in a Neutral ending, the only person there is the Human, and humans cannot absorb human souls, nor can monsters absorb monster souls. This means that they just fade away after being released from their Soul Jar. In the True Pacifist ending, Asriel says that he can't bear to keep the souls imprisoned within him, and lets them all go, the six human souls included (which would then fade into nothing).
    • If you return to the room with the coffins at the end of the True Pacifist route, you find that they're all now open. Make of this what you will.

W. D. Gaster

This is one of his speculated sprites.
Beware of the man who speaks in hands.
—The Riverperson

Dr. W. D. Gaster was, according to his followers, the royal scientist before Alphys and created the Core, but was erased from time and space after some sort of accident. He isn't actually present in the game, but in dummied data; all information about him could be only accessed by editing files, and stuff speculated to be related with him is often written in Wingdings font. Even his actual appearance is unknown; there are sprites in two dummied-out rooms that are speculated to be him and fandom bases their speculations in the one we use in this section. After a certain actualization of the game, however, you can have aleatory access to the random events hinting about his (former/possibly current) existence without actually having to edit files; whatever it means in the lore of the game is a mystery.

Tropes exhibited by this character include:
  • And I Must Scream: You can find figments of him through the world lamenting his horrible fate.
  • Beyond the Impossible: His report mentions negative photon readings, which is a physical impossibility.
  • Body Horror: One of the NPCs who speaks of him is holding a miniature of his head.
  • Dem Bones: The font Theme Naming convention he shares with Sans and Papyrus, as well as the appearance of spr_mysterman, heavily suggest that he is/was a skeleton monster.
  • Dummied Out
  • Eldritch Abomination: He exists, yet he doesn't.
  • Expy His plain white design with black clothes, his ambigious nature, and association with static, he has shades of Slenderman.
  • Gone Horribly Right: It's a common headcanon that his machine was created to solve the problem of the Barrier, but whatever timespace shenanigans it would have using ended up affecting HIM as well.
  • Hoist by His Own Petard: Non-villainous version. Gaster was the one who designed and built the Core, providing the Underground with electricity. Unfortunately, an accident caused him to plummet into one of his creations (presumably either the Core or Sans' broken machine) the damage of which was so severe that it blasted him and possibly some of his colleagues across time and space.
  • Meaningful Name: Everything presumed written by him is in Wingdings font, and his initials are W.D.
  • The Missingno: His existence is an exploration of this trope, and what such a character would be like within the context of the game world itself.
  • Morally-Ambiguous Doctorate: He's a rather ominous doctor, between his dangerous creations and the fear of those NPCs which discuss him.
  • Number of the Beast: There is data in the game for a possible battle encounter against Gaster. For some reason or other, his attributes have the number 6 in every digit. 66 is also the Fun value you needed to get the door to his room to appear at Waterfall.
  • The Professor: A tall skeleton(?) with a goofy grin who speaks entirely in Wingdings. Also the most brilliant mind in all of monsterkind.
  • Ret-Gone: Or Is It? Apparently, whatever fate befell Gaster took his history with it, as even learning his name requires extreme luck and/or messing with the code.
  • Riddle for the Ages: While there are some "models" of Gaster that are more popular in fanon interpretation, at the end of the day, he as a character is an absolute mystery on just about every level. We have no idea what he was like as a person, what his goals or relationships were, or even his exact fate and how it befell him; all that is known for certain about him is his former role as the royal scientist, the fact that he no longer properly exists and likely never will again, and the fact that he has some kind of important connection with Sans.
  • Shout Out: The sprite he is most commonly associated with has more than a passing resemblance to Uboa.
  • Tempting Fate: One of the grey NPCs that explains the story behind Gaster says he has nothing to fear from him, since he has a piece of him. He vanishes immediately after he's done talking. A notable case because none of the other grey NPCs disappear until you leave their rooms... and because his disappearance is accompanied by the exact same sound that plays when Gaster himself (or, at least, whatever apparition serves as his image shown above) vanishes too.
  • Things Monsters Was Not Meant to Know
  • The Unintelligible: Like Sans and Papyrus, Gaster speaks in the font he is named after... in this case, Wingdings, which... probably isn't a "dialect" the player will understand. Fortunately, lots of translation tools exist online.
  • Vagueness Is Coming: Among Alphys' reports, there is the elusive Entry #17 in which Gaster talks about doing research on an ever expanding darkness. He then asks what two unknown people think about it.
  • Wham! Line: The below quote in the Gaster's Followers section.
    • The famous Entry 17 in the True Lab, which can only be accessed by editing data, have a disturbing hint on what happened with him and that he probably wasn't alone during the experiment that booted him out of reality.

The Gaster Followers

Well, I needn't gossip. After all, it's rude to talk about someone who's listening.

A group of characters that appear randomly under certain hidden variables in game and have information about Gaster.

Tropes exhibited by these characters include:
  • Ambiguous Gender: All four of them are never given a canon gender. Most players assume "Goner Kid" is female because of how it looks like it's wearing a bow, compared to Monster Kid's having horns.
  • And I Must Scream: Similarly to Gaster, none of them appear in the game itself without altering the game's coding until the 1.0.1 patch, where they can appear randomly.
  • Color Coded for Your Convenience: They have grey overworld sprites, to distinguish them from the more colorful regular monsters.
  • Deliberately Monochrome: All four of them are greyscale.
  • Dummied Out
  • The Last of These Is Not Like the Others: Unlike the rest of the followers, Gaster Follower 3 is not a Palette Swap of an already existing NPC.
  • Monochromatic Eyes: "Goner Kid" has completely blank eyes.
  • Mr. Exposition: All three of the Gaster Followers only talk about what happened to W.D. Gaster in some form. "Goner Kid" is a little more subtle with their exposition.
  • Oracular Head: The "head" in Gaster Follower 2's hand is the one talking.
  • Palette Swap: Gaster Followers 1 and 2 and "Goner Kid" are all palette swaps of several of the preexisting monster characters. Notable in that, despite being palette swaps, they all have notable differences from the "normal" versions.
    • "Goner Kid" = Monster Kid.
    • Gaster Follower 1 = the ficus licker in MTT Resort.
    • Gaster Follower 2 = the monster holding the donut at the Spider Bake Sale.
  • Properly Paranoid: One of the followers believes it'd be "rude to talk about someone who's listening" in regards to Gaster. It might not be paranoia given what happens to one of the other followers holding "a piece of" Gaster.
  • Ret-Gone
  • Rhymes on a Dime: Gaster Follower 2 does this if you look closely.
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