Undertale/Characters

The Human
A human child who fell into the Underground. They are the character the player controls during the game. .


 * 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.
 * 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 . 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"..
 * 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.
 * 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:.
 * 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.
 * 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.
 * 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.

Flowey
"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.


 * 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..
 * : After.
 * 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.
 * 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.
 * : Except in the.
 * Book Ends: Flowey is.
 * 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..
 * 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.
 * Cruel and Unusual Death: On the worst ending, Flowey attempts to beg for mercy, only to be utterly mutilated and cut in half.
 * Defiant to the End:.
 * 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..
 * The Dragon: Somewhat becomes this to you in the Genocide run, completing puzzles for you and making your playthrough quicker..
 * 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.
 * 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.
 * 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,.
 * : Flowey is one of three or so bosses the player can fight at the end of a route..
 * 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?
 * Formerly Walking Spoiler: Due to Late Arrival Spoiler and Pop Culture 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.
 * 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. {{spoiler|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 observe. He is also fond of morphing his face to imitate other monsters. {{spoiler|All of those are combined and exploited in his boss fight with his Omega form having a particularly deranged one}}.
 * {{spoiler|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 {{spoiler|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}}.
 * {{spoiler|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.
 * {{spoiler|Omnicidal Maniac}}: Flowey wants to {{spoiler|destroy EVERYONE, humans and monsters alike}}.
 * {{spoiler|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: {{spoiler|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 {{spoiler|Asriel's consciousness, devoid of actual emotions, trapped inside a flower}}.
 * {{spoiler|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}}.
 * {{spoiler|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 {{spoiler|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". {{spoiler| 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. {{spoiler|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.
 * {{spoiler|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?: {{spoiler|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}}.
 * {{spoiler|Woobie, Destroyer of Worlds}}: Flowey's {{spoiler|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.
 * 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.
 * {{spoiler|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?: {{spoiler|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}}.
 * {{spoiler|Woobie, Destroyer of Worlds}}: Flowey's {{spoiler|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.

{{hardline}}

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). .


 * 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.
 * 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.
 * 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.
 * Leitmotif: "Heartache".
 * Memetic Sex Goddess: Confusingly enough, considering that she is a several-thousand-year-old anthropomorphic goat. But apparently that's the appeal.
 * 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.
 * : 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.
 * 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.
 * 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.
 * 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. .


 * 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..
 * 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 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,.
 * 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.
 * 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).
 * 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:.
 * Hero Antagonist:.
 * 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..
 * Joke Character: 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 innappropriate 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.
 * 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:.
 * 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..
 * 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 Frisk 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..
 * 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.
 * 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".
 * 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
"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.


 * 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.
 * Ambiguously Human: See Sans' example above. Though there's not much evidence from Papyrus specifically, he qualifies by association due to them being (presumably blood-related) brothers.
 * 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.
 * 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: "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..
 * 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.
 * 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.


 * 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.
 * 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.
 * BFS: 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. 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.
 * 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:.
 * 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.
 * 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.
 * 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:.
 * 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:.
 * 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.
 * 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..
 * 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.
 * 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.
 * 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.
 * During a Neutral/Pacifist run, if the player.
 * During a.
 * 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.
 * 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 Swears A Lot: 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.
 * 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.


 * 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..
 * Barefoot Cartoon Animal
 * Bitch in Sheep's Clothing
 * 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..
 * 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.
 * Everyone Can See It: When you go on a date with her, she makes it very clear that she's attracted to her best friend Undyne. Mettaton comments on how obvious it is if you bring it up during his quiz, and even Papyrus seems to connect the dots, judging by one possible phone call.
 * Expy: She's basically the sexy genderbent version of Francis from Super Paper Mario.
 * 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 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:.
 * 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..
 * 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.
 * 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. .


 * 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.
 * 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.
 * 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.
 * 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, 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, . 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.
 * 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" pun.
 * 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.
 * 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: 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.".
 * 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,.
 * 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 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:.
 * 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:.
 * 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:.

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.


 * Affably Evil: He offers you tea, before realizing that there's no time for that..
 * Anti-Villain
 * 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.
 * 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:.
 * 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..
 * 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.
 * 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.
 * It's arguable whether this trope truly applies because Asgore KNOWS what he's doing isn't morally justifiable, but he feels he needs to do these things for the greater good, thus he does see his actions as the right thing overall.
 * Nice Guy:.
 * : During a Neutral run. Luckily, this trope is averted during a True Pacifist run.
 * Slave to PR: Played with. He is legitimately as nice, helpful and kind as his subjects make him to be..
 * 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.
 * Well-Intentioned Extremist: Asgore takes it a step further by wanting to clear the surface so that monsters can live there alone peacefully.
 * Well-Intentioned Extremist: Asgore takes it a step further by wanting to clear the surface so that monsters can live there alone peacefully.
 * Well-Intentioned Extremist: Asgore takes it a step further by wanting to clear the surface so that monsters can live there alone peacefully.

Napstablook
"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.


 * Achievements in Ignorance:.
 * all lowercase letters: He talks this way.
 * Bedsheet Ghost
 * The Eeyore: He is downbeat to almost comedic levels.
 * Punny Name: His name is a pun on the old sharing program Napster.

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.


 * Angry Guard Dog: The image he evokes.
 * Knife Nut: Fond of knives, judging for his sprite and attacks.
 * The Stoner: Near his station, there are several smoked dog treats.

Dogamy and Dogaressa
"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.


 * An Axe To Grind: They attack with their gigantic axes.
 * The Nose Knows: Their main ability, albeit theirs can be fooled.
 * Sickeningly Sweethearts: The Dogi are said to call each other overly cute names during battle.

Greater Dog


Another dog sentry in Snowdin Forest.


 * Big Friendly Dog: Greater Dog looks gigantic and intimidating, but all it wants is some TLC, and will gladly leave you alone when it 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...
 * Go Fetch: An important part of sparing him.

Glyde


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


 * 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

Mad Dummy
"Foolish. Foolish! FOOLISH!"

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


 * Bad Boss: He is very rude to his underlings, firing them when the player avoids their attacks.
 * Hair-Trigger Temper: No matter what the player does when examining him, he will take offense and attack.
 * Knife Nut: He will try to knife you. Fortunately, he has only one knife.

Royal Guards
"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.


 * Manly Gay/Straight Gay: Royal Guard 01.
 * Valley Girl: Their speech is a mix of valley girl and stereotypical jock speech.

Muffet
"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. .


 * Bribing Your Way to Victory: In battle, you can pay her to lower her defense in the next turn. Also, eating an Spider-made product makes her immediately spareable.
 * Cute Monster Girl: Though, considering that female spiders eat their mate...
 * Elegant Gothic Lolita: Her looks and dress evokes it.
 * Hypocritical Humor: Whenever someone refuses to buy her wares, she considers them to be "greedy". Meanwhile, she's incredibly greedy herself..
 * Noblewoman's Laugh: "Ahuhuhuhu".
 * Well Intentioned Extremist: She just want to reunite the spider clans spread in the Underground. If to do so, she has to overcharge her confections and accept the occasional contract killing odd job to get the funds for her plan, so it will be!

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.


 * 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.
 * Guide Dang It: His fight is only accessible October 10 at 8 PM (thankfully, the room itself is easier to find). If you manage to find the room during the Bad route while fulfilling the conditions to encounter him, instead of him, you will find a note saying "Art club have been suspended."
 * Secret Character

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).


 * Ambiguous Gender: It's never said whether Monster Kid is a boy or a girl..
 * Break the Cutie: Several ways of doing this..
 * Hero Worshipper: They admire Undyne greatly, and traverse Waterfall for a chance of meet her..

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.


 * The Ditz: Believes that an cold, snowy area is the perfect location for enjoying ice cream.
 * The Pollyanna: He is very upbeat and hopeful his business will take out.

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.


 * Funny Animal: She is an humanoid rabbit.
 * Meek Townsman
 * Shop Keeper

Gerson
"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.


 * Cool Old Guy: He's pretty friendly and playful (assuming you're not in a No Mercy run at least), if only a bit senile.
 * Long Lived: He actually fought in the first Human-Monster war millennia ago.
 * Rambling Old Man Monologue: Some of the stuff he says has this vibe.
 * Retired Badass: He used to be "Gerson, the Hammer of Justice".
 * Shop Keeper

The Riverperson
"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.

"I am the riverman. Or am I the riverwoman...? It doesn't really matter."
 * Ambiguous Gender: Lampshaded:


 * Black Cloak: Their emblematic outfit.
 * Cryptic Conversation
 * Verbal Tic: Tends to begin their speeches with "Tra la la".

Temmies
"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.


 * Cloudcuckoolander/The Ditz: All of tem. Their shopkeeper is the only one in the game that will buy the player's stuff.
 * Cuteness Proximity: Their already ditzy demeanor gets worse in the presence of whatever they believe is cute (which includes humans like you), and they will try to pet it. Conversely, they die in the presence of uncute stuff (like the muscular monster Aaron).
 * Odd Name Out: Bob (who also is the only one who speaks standard English).
 * Out of Character Alert: If the Temmie shopkeeper is refused on their offers to buy stuff, they will become deathly serious and talk in standard English instead of the whimsical way Temmies usually talk.
 * 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.
 * Ridiculously Cute Critter: Just see tem!
 * Shout Out: To the Mr. Saturn in Earthbound.
 * Trademark Favorite Food: Temmie Flakes.
 * Verbal Tic/Verbal Tic Name: "Tem".

Bratty and Catty
"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).


 * Big Sister Worship: Towards Alphys, of all people.
 * 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.
 * 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.
 * Meaningful Name: Bratty and Catty are Exactly What It Says on the Tin.
 * Stealth Punny Name: They are an alley-gator and an alley-cat who talk like v-alley girls.
 * Shop Keeper
 * 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.


 * Broken Pedestal: He used to be a fan of Mettaton before actually working for him.
 * Burger Fool
 * The Cynic: Pretty cynical about the world.
 * Embarrassing Nickname: 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.
 * 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
 * Off-Model: Invoked. All of his expressions are radically different.
 * Only Known by Their Nickname: And an embarrassing one to boot.
 * 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.
 * 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. .

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 Bad 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.


 * Ambiguous Gender: Like the player character, their gender isn't actually specified and is referred by "them" pronouns.
 * Big Brother Bully: Implied by.
 * This is taken to the extreme.
 * Creepy Child: Even before, it was clear that there was something off about this kid from the start. After all,.
 * Humans Are the Real Monsters: Apparently, the Fallen Child believed this,.
 * Insert Player Name Here: . In fanworks, they are usually called "Chara", as it was the the placeholder name used in promotional screenshots,.
 * Knight Templar: Is implied to he 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.
 * Lemony Narrator: If you buy into the "Narrator Fallen Child" theory, they are quite the sarcastic little fellow, prone to puns and easily exasperated.
 * 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.
 * Not So Different: Their deeds are all one massive reflection of.
 * Shadow Archetype: While their actual morality is ambiguous, they have shadowy and demonic themes going on . There is a reason even the kindest fan depictions deliberately contrast them with and play up  apparent morality.
 * Trademark Favorite Food: Chocolate.
 * : Maybe.
 * Well-Intentioned Extremist: According to Asriel, they really wanted to help the monsters. Pity about their methods....
 * You Cannot Grasp the True Form: Ultimately, it's not clear.
 * Well-Intentioned Extremist: According to Asriel, they really wanted to help the monsters. Pity about their methods....
 * You Cannot Grasp the True Form: Ultimately, it's not clear.

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

Asriel Dreemurr was the son of Asgore. He was the one who found the Fallen Human, 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. .


 * Meaningful Name: His name is very similar in convention to angels names, ...
 * : His goal.
 * Meaningful Name: His name is very similar in convention to angels names, ...
 * : His goal.
 * Meaningful Name: His name is very similar in convention to angels names, ...
 * : His goal.
 * : His goal.

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


 * Color Coded for Your Convenience
 * We Hardly Knew Ye

W. D. Gaster
"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.


 * Cosmic Horror Story: It's stated that he wasn't just erased, but scattered across time and space. And it's implied he have some level of control about the game's reality: if you attempt to introduce "Gaster" in the naming screen, the game returns to the intro (in the PC version) or outright crashes (in the PS4 version).
 * Dummied Out
 * Meaningful Name: Everything presumed written by him is in Wingdings font, and his initials are W.D.
 * Ret-Gone: Or Is It?
 * Shout Out: The sprite he is most commonly associated with has more than a passing resemblance to Uboa.
 * Things Monsters Was Not Meant to Know
 * 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.

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.


 * Color Coded for Your Convenience: They have grey overworld sprites, to distinguish them from the more colorful regular monsters.
 * Dummied Out
 * Ret-Gone