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.
 * 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.
 * 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.
 * 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.
 * 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.
 * Power of Love: They can be so good at this power that.
 * Tomato in the Mirror:.
 * Tomato in the Mirror:.

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.


 * : After.
 * And I Must Scream: Flowey is a flower, thus.
 * : Except in the.
 * Book Ends: Flowey is.
 * 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.
 * 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.
 * Nightmare Face: He has an assortment of those. Just observe. He is also fond of morphing his face to imitate other monsters..
 * Not So Different: The player and Flowey, most notably if you.
 * : Flowey wants to.
 * Puppeteer Parasite: Often portrayed as one of these in fanworks.
 * The Reveal: Flowey is actually.
 * Schmuck Bait: After.
 * Stalker with a Crush/Stalker Without a Crush: At some points of the game, backtracking will reveal that Flowey was following the player.
 * Teleport Spam: Basically how he gets around throughout the game.
 * Who Wants to Live Forever?:.
 * : Flowey's.
 * The Reveal: Flowey is actually.
 * Schmuck Bait: After.
 * Stalker with a Crush/Stalker Without a Crush: At some points of the game, backtracking will reveal that Flowey was following the player.
 * Teleport Spam: Basically how he gets around throughout the game.
 * Who Wants to Live Forever?:.
 * : Flowey's.

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). .


 * Barefoot Cartoon Animal
 * Beware the Nice Ones: Toriel is powerful, and will give you a taste of it if you decide to ignore her warnings.
 * Does Not Like Shoes
 * Hopeless Boss Fight: Except that.
 * Leitmotif: "Heartache".
 * Memetic Sex Goddess: Confusingly enough, considering that she is a several-thousand-year-old anthropomorphic goat.
 * Mother Goat
 * My Beloved Smother: Toriel treats you as her child, and keeps a close eye on you.
 * Nice Lady
 * Punny Name: Her name is a pun in "Tutorial".
 * : Depending on the route the player takes.
 * Stop Helping Me!: While well intentioned, her help can be a little hindering.

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. .


 * all lowercase letters: His way of speak, on top of his characteristic font.
 * 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 Fun: He is somewhat big boned, he is constantly telling jokes, and is well known and loved by a lot of characters.
 * Brilliant but Lazy: Sans is a self-described lazy skeleton without a care in the world. However,.
 * Dem Bones
 * 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).
 * Good Is Not Soft:.
 * Hero Antagonist:.
 * 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.
 * 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) 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.
 * Neutral No Longer:.
 * Obfuscating Stupidity: The more you know him, the more apparent it becomes that a good part of his goofiness is faked.
 * Pungeon Master: The main purveyor of puns in the game.
 * Sad Clown: As the plot advances he is increasingly shown to be one..
 * Skull for a Head
 * The Slacker: Very much so.
 * 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.
 * Walking Spoiler
 * 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.
 * 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.

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 pf puzzles and cooking.


 * Annoying Laugh: He laughs "NYEH HEH HEH!!" constantly.
 * Annoying Younger Sibling: Of Sans. Albeit he is annoying only from the viewer perspective; in universe, Sans is pretty proud of him and takes his most annoying qualities in stride.
 * Awesome Ego: Refers to himself as "The Great Papyrus" constantly.
 * 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.
 * 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.
 * 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
 * Anti-Heroine: Of the "actually heroic but still a jackass" variety.
 * Blood Knight
 * 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
 * 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
 * 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
 * Walking Spoiler

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 actaully be a pretty fun guy when not tryng 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 resonsible 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, but it's revealed before his boss fight he dosen't actually hate humanity and desires to stop Asgore from starting the war. He would be an outright Well Intentioned Extremist if not for his ego.
 * Evil Counterpart/Foil: To Papyrus (they even get one or two Ship Tease moments with one another). Both have huge egos, and both are very campy, and both act extremely campy and over the top. However, Papyrus is very low level if having ambitions. Mettaton has a very high position in society. Papyrus is described as a "human hating fanatic" by Sans which shows, but Mettaton is revealed to not have anything against humanity and has separate goals. Also whereas Papyrus worships Undyne and strides for her approval, Mettaton and Undyne seem to have a rivalry. The bigest difference is that while both have egos and large ambitions, Mettaton is willing to kill to fullfill his goals.
 * Faux Affably Evil: Mixed with Affably Evil, but they have an absolutely jovial and over the top sense of humour and displays it while tryng to murder you a small child the stand out is probably 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 before a few sentences later saying that his ultimate goal is to be worshipped like a god
 * 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
 * Well-Intentioned Extremist
 * Well-Intentioned Extremist

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

Greater Dog


Another dog sentry in Snowdin Forest.


 * Big Friendly Dog
 * 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 voids 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.
 * Well Intentioned Extremist: She just want to reunite the spider clans spread in the Underground.

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 accesible 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
 * 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:


 * 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
 * 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.
 * 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 they 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.
 * 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.
 * : {{spoiler|Their plan to free the monsters involved committing suicide via buttercup poisoning (a very unpleasant way to die) and let their soul being taken by Asriel}.
 * 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.
 * 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