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.
 * : 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 nNutral 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.
 * Dem Bones
 * The Ditz: He is kinda off there. One example: the outfit he wears, which he calls his "Battle body" and never takes it off, was originally created for a costume party.
 * Foolish Sibling, Responsible Sibling: He seems and acts like the responsible one, being the one who keeps house and constantly has to nag on Sans to keep with his responsibilities, but his childish and hammy nature makes him more of a fool than he can admit.
 * 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.
 * Good Is Dumb: Papyrus is not actually that dumb, but he is very naive.
 * I Just Want to Have Friends: His main motivation.
 * 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.
 * Large Ham: Highly boastful, with No Indoor Voice.
 * Leitmotif: "Bonetrousle".
 * Lethal Chef: He loves cooking pasta, but he is terrible at it. Part of the reason is that he learns from Undyne, who is as bad as he is.
 * Man Child: He's a tall skeleton who's really immature.
 * 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.
 * 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.
 * 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...
 * Skull for a Head
 * Trademark Favorite Food: Spaghetti. He will let you know about this fact, many times..
 * "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.
 * "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.

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?
 * Anti-Heroine: Of the "actually heroic but still a jackass" variety.
 * 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.
 * The Brute
 * Cute Monster Girl: She is a fish girl.
 * 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.
 * Eyepatch of Power: Just look at her.
 * 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.
 * Heel Face Turn: In a Pacifist run, she.
 * Hero Antagonist:.
 * Heroic Resolve
 * : When the player.
 * Heroic Spirit:.
 * 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.
 * 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 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..
 * 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.
 * Memetic Sex Goddess: Nearly to Toriel levels, in fact.
 * Pet the Dog: Several cases where she does this.
 * During a Neutral/Pacifist run, if the player.
 * During a.
 * Tsundere: When you attempt to befriend her during a Pacifist run, she clearly does warm up to you, while trying to play it cool, still calling you a "dork" and threatening to attack you.
 * Yandere: She doesn't lose her violent self when you try being her friend.
 * Tsundere: When you attempt to befriend her during a Pacifist run, she clearly does warm up to you, while trying to play it cool, still calling you a "dork" and threatening to attack you.
 * 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 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.
 * Brain With A Manual Control: Well, as demonstrated by Undyne in Alphys VS Undyne, at least.
 * Break The Cutie: It's a long process for poor Alphys..
 * Butt Monkey: Nothing goes well for thr poor doctor.
 * Cute Clumsy Girl
 * Cute Monster Girl
 * Does Not Like Shoes
 * Expy: She's basically the sexy genderbent version of Francis from Super Paper Mario.
 * Fat Best Friend: Of Undyne, at least.
 * Genius Ditz
 * Labcoat of Science and Medicine
 * Luminescent Blush
 * Memetic Sex Goddess: Albeit mostly in fanart.
 * 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: And an opinionated one.
 * Scientific Mother:.
 * Shrinking Violet
 * 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..
 * Tomboy and Girly Girl: Very clearly the girly girl to Undyne's tomboy.
 * 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.
 * 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.

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.
 * 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.
 * Dragon In Chief: who he ends up upstaging after this is revealed.
 * Even Evil Has Standards: Say what you will about his morals, He would be an outright Well-Intentioned Extremist if not for his ego.
 * 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.
 * 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.".
 * Heel Face Turn: In the Pacificst run and even in a Neutral run,.
 * Large Ham: Highly melodramatic, and always speaking in caps.
 * 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.
 * Mr. Fanservice:.
 * Pragmatic Villainy: Mettaton's primary concern is his audience, which is more important to him than killing you. Though he multi-tasks quite well...
 * Not So Well Intentioned Extremist: He says before his last boss fight that he wants to stop the war, then a few sentences later saying that his ultimate goal is to be worshiped like a god.to be fair they DO believe in their cause but as a side benefit.
 * The Reveal:.
 * Zero Effort Boss: Mettaton NEO is no match for.

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
 * Barefoot Cartoon Animal
 * The Big Guy
 * The Brute: Of the Dreemurr family.
 * Does Not Like Shoes
 * Embarrassing Nickname: King Fluffybuns, as he is called by Gerson.
 * Final Boss:.
 * 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..
 * 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