Follow TV Tropes


Characters / Undertale - Spoiler Characters

Go To

Top Index | Major (The Human Child, Flowey, Toriel, Sans, Papyrus, Undyne, Alphys, Mettaton, Asgore Dreemurr) | Minor | Monsters | Spoilers

As the name indicates, everyone on this page is a Walking Spoiler, even more than the already spoilery main characters. Even their very existence is a major plot twist. Thus this page contains no spoiler-marking at all. You've been warned. You wouldn't want a bad time, would you?


    open/close all folders 

  • Walking Spoiler:
    • The six human souls play a crucial role in beating a major boss. Problem is, that boss is built around trying to make you feel hopeless, so if you know how to beat him going in, the effect is ruined.
    • Asriel, and in particular his existence as Flowey, spoils the pacifist and genocide endings.
    • The Amalgamates spoil much of the pacifist ending since they are only found in the secret area known as the True Lab, where Flowey was created.
    • Chara/The Fallen Child spoils the Genocide ending, and to a lesser extent the Pacifist and Neutral endings as well. Turns out the child from the opening movie isn't the character you're playing as, and in a Genocide run, that first Fallen Child destroys the world.
    • You, as in, being a separate entity from the actual player character, spoils the fourth wall breaking aspects of the Pacifist and genocide endings
    • W.D. Gaster and his followers are characters hidden in the game's code with an unclear identity.

    Human SOULs
You're filled with DETERMINATION.

The six humans who fell down into the underground before the Player Character did. Their SOULs were harvested for the sake of breaking the barrier imprisoning the monsters and exterminating the human race. You can find their old weapons and armour scattered throughout the world.

  • And I Must Scream: They're seemingly unable to do anything while they're trapped in the SOUL jars.
  • Ambiguous Gender: Like Frisk and Chara, their genders are never revealed. Most fans agree that Orange and Yellownote  are male, while Blue and Cyan note  are female. And even then that's not clear cut, as a good chunk of fanarts represent Yellow as a (cow)girl, and some even interpret the ribbon as a bow tie worn by a boy. No clues in the game are given about Green and Purple.
  • Ambiguously Evil: One of them (the blue SOUL) likely killed at least one monster, possibly more, but we have no idea why or how.
  • Asshole Victim: Maybe some of them. It's implied that at least a couple of them managed to rack up a lot of EXP before they were killed, most prominently the blue soul (whose items are described as "dangerous" and covered in dustnote ) and the yellow soul (who had a real gun). It's left ambiguous, however, if they did this for actually malicious reasons, or if they did it out of (legitimate, since unlike the player character they only have one life) self-defense, or a desperation to avoid being killed and forcibly used as a weapon to destroy everyone they love.
  • Barred from the Afterlife: Forced to stay rooted in the mortal world after death through unexplained technology. In the Neutral and Pacifist endings, they're all finally set free.
  • Big Damn Heroes: After calling out to them enough, they resonate with Frisk and begin turning the fight against Flowey. And when he uses his save state powers to undo his defeat, they unite to utterly destroy him in one shot, saving Frisk from a truly unwinnable situation.
  • Chef of Iron: Implied of the green SOUL, who used a frying pan as a weapon and wore an apron.
  • Colour-Coded for Your Convenience: Separately from your red SOUL and grey monster SOULs; they come in orange, yellow, green, cyan, purple, and blue. Notably, the colors correspond to the various colors that bosses can turn your SOUL, as well as the three different attack colors.
    • The colors are indicative of the humans' greatest virtue before they died:
      • Cyan - Patience
      • Orange - Bravery
      • Blue - Integrity
      • Purple - Perseverance
      • Green - Kindness
      • Yellow - Justice
  • Dance Battler: The blue SOUL was, which explains why ballet shoes are a weapon you can acquire.
  • Determinator: The purple SOUL's special trait was perseverance. Though obviously they weren't as determined as Flowey or Frisk.
  • Empathic Weapon: Even after death, they can still feel emotion and respond to your fight against Flowey.
  • Everyone Has Standards:
    • Despite their rather unclear morality, all of them aid you during the battle against Flowey and eventually rebel against his control to save you.
    • Also, one of the rare things that's sure about them is that they all met Toriel in the Ruins. Since she's still there at the beginning of the game, none of them harmed her. Therefore, even the more morally ambiguous of them never thought of harming her, let alone doing a Genocide Run.
  • Fatal Flaw: Can be inferred, judging by the location and effects of their equipment and/or their SOUL modes.
    • None of them had enough Determination to LOAD or SAVE (at least, not enough to surpass Flowey's), meaning they only had one life to live. Once they died, that was it.
    • Cyan: Cyan attacks in the game are dodged by standing still, implying that a cyan-colored SOUL won't move or dodge attacks. Cyan's journey was the shortest, and their equipment is found in the Ruins, the earliest part of the game. That, or they were too patient. They waited in place absolutely sure that they'll be saved and starved to death.
    • Orange: Orange attacks are dodged by moving through them. An orange SOUL would be constantly moving around and unable to dodge cyan attacks, which are used by the guard dogs in Snowdin. Additionally, the Ball Game mentions them "rush[ing] fists-first through all obstacles", implying that they were reckless and got in over their head, leading to their death.
    • Blue: A blue SOUL is affected by gravity and can only make short jumps before falling to the bottom of the bullet box. Many enemies in Waterfall, where Blue's equipment is found, have attacks that are difficult to dodge at the bottom of the box (Aaron's CHECK text even says as much).
    • Purple: Their equipment increases invincibility after taking damage, requiring them to get hit in order to make the best use of their weapons. They likely allowed themselves to get hit too many times and died.
    • Green: The green SOUL mode makes the player's soul immobile and allows them to block attacks from a single direction. Their equipment is found in Hotland, where there are multiple enemies (Pyrope, the Royal Guards) whose bullets come from all directions.
    • Yellow: They had a gun for a weapon and possibly made it the farthest (along with Green), but it's empty when the player gets it, implying that they lost their last line of defense when they ran out of bullets. Whoops.
  • Frying Pan of Doom: The green SOUL's weapon.
  • Hero of Another Story: Or Villain of Another Story, depending on whether or not they (or some of them) actually were evil. They fell into a predicament similar to Frisk's and, just like them, they went on a quest to try to go back in their world. However, they are already dead when the game begins, leaving behind them a few items and very few clues on what their stories were.
  • Hot-Blooded: The orange SOUL, judging by their associated trait, Bravery, and the flavor text in the Ball Game.
    Ball Game, orange flag: You are the kind of person who rushes fists-first through all obstacles.
  • Human Sacrifice: They were killed to make someone powerful enough to break the barrier.
  • Improbable Weapon User: Including ballerina shoes, a notebook, and a frying pan.
  • Killed Off for Real: They fell in various points during the Underground, it's implied the farthest any of the other souls made it was Hotland (the green and possibly the yellow one, depending on where Catty and Bratty got the yellow SOUL's equipment from).
  • Knife Nut: The cyan SOUL used a toy knife, which can be found in the Ruins.
  • Leitmotif: A different remix of "Your Best Friend" for each of them plays when they are fought during the confrontation with Omega Flowey. Cyan's and Orange's versions are higher-pitched than the original, Purple's and Yellow's versions are lower-pitched, Blue's uses a whistle instead of chiptune, and Green's uses a piano.
  • Living MacGuffin: Not so much living anymore. Still semiconscious, though.
  • Nice Hat: The Cowboy Hat belonged to the yellow SOUL.
  • Playing with Fire: Getting past the green SOUL during Omega Flowey's fight requires dodging waves of flames tossed from three frying pans.
  • Plot Coupon: They're six differently colored (but otherwise identical) objects that are being collected in order to accomplish a goal, which clearly resembles a common type of plot coupon in RPGs. The difference with these? You're not collecting them; the monsters are, and the player character happens to be the last one they need.
  • Posthumous Character: All of them died and their souls were taken by Asgore before the game began; the exact circumstances of their deaths, either at the hands of Asgore himself or someone else, isn't stated.
  • Power-Up Food: When turned to Frisk's side, the green SOUL tosses healing bullets shaped like fried eggs.
  • Rainbow Motif: Together with Frisk's red heart. This also pops up in with 7 coffins with the same color hearts (with the red one being closed), and with Photoshop Flowey cycling through the entire spectrum in his demise.
  • Riddle for the Ages: Why did they climb the mountain and fall into the Underground, what were their personalities like, and how did they die?
  • Ripple Effect-Proof Memory: Them having this is the only saving grace in the Photoshop Flowey fight. Even if you die and Flowey reloads, they remember that you've called to them, and they still want to help you. This contributes to them rebelling after you "defeat" Flowey and he reminds you that he can just reload back to full health.
  • Shout-Out: Much like Frisk's Stick, their weapons, with the exception of the Torn Notebook, belong to classes of Mother weapons:
    • Toy Knife: Teddy from the first game had knives as his first two weapons, though these would be outshone by a Sword and Katana.
    • Tough Glove: Kumatora from the third game used gloves.
    • Ballet Shoes: Duster from the third game would kick with his shoes, though none of them were ballet shoes.
    • Burnt Pan: Ana and Paula from the first two games fought with frying pans.
    • Empty Gun: Lloyd and Jeff, also from the first two games, wielded guns.
  • Take Up My Sword: All of the Gear in the game, with exception to the Temmie Armor and the items in New Home were gear used by them before they died. In the battle against Flowey, it is even shown in attack phases which colored soul used which weapon:
    • Cyan = Toy Knife and Faded Ribbon
    • Orange = Tough Glove and Manly Bandanna
    • Blue = Ballet Shoes and Old Tutu
    • Purple = Torn Notebook and Cloudy Glasses
    • Green = Burnt Pan and Stained Apron
    • Yellow = Empty Gun and Cowboy Hat
  • Unknown Character: Despite their importance in the story and the Neutral and True Pacifist Endings, almost all information on them is either implied or completely left for interpretation. Even their names are unknown, as in the room with their coffins, only Chara's can be readnote .
  • What Happened to the Mouse?: They're mentioned as missing in the Neutral and True endings, but what happened otherwise is unexplained. Simple Logic would state that in a Neutral ending, the only person there is Frisk, and Humans cannot absorb Human souls, nor can Monsters absorb Monster souls. This means that they just fade away after being released from their Soul Jar. In the True Pacifist ending, Asriel says that he can't bear to keep the souls imprisoned within him, and lets them all go, the six human souls included.
    • If you return to the room with the coffins at the end of the True Pacifist route, you find that they're all now open. Make of this what you will.
  • Word of Dante: Everyone in the fandom seems to operate on the assumption that they were all children like the human child and Chara, but there's no real evidence of this.

    The Amalgamates
no No NO NO NO NO NOnote 

A group of abominations created by accident from a terrible experiment involving Determination.

  • Alien Geometries: Assuming its sprite is meant to be taken literally, Endogeny appears to somehow have a series of dog faces and bodies in the negative space between its legs.
  • And I Must Scream: All of them (especially Lemon Bread) are at least slightly aware of their plight, but they can't do anything about it due to Alphys keeping them a secret, and they can't die by normal means.
    Lemon Bread: Welcome to my special hell.
  • Assist Character: The Reaper Bird doesn't attack directly; it instead has the help of "Everyman", a bird-like humanoid that attacks in bizarre ways.
  • Big Friendly Dog: If you coax Endogeny over, you can pet it like the other dogs. It's described as being very affectionate in some of the quotes.
  • Blob Monster: Endogeny is described as being amorphous, and is a vaguely dog-shaped blob that can disperse itself into floating particles.
  • Body Horror: Several "normal" monsters combined into one.
  • Call-Back: By the time you face them, you'll likely have faced all of their "components" earlier in the game. The method of Sparing them tends to be similar. Special mention goes to Endogeny, whose Spare method is exactly the same as that of Greater Dog. Once it's pacified, the background music changes to "Dogsong", which played in the fight against Greater Dog.
  • Came Back Wrong: The result of Alphys' experiments with injecting monster souls with Determination.
  • Dark Is Not Evil: They're terrifying to look at, the reason behind their existence is horrifying, and the sequence in which you meet them is probably the closest the game ever comes to being a straight-up horror game... but none of them seem to sincerely want to hurt you (outside of maybe Lemon Bread, and even then that's more you being the first target for... their... frustrations in years), they all back off once Alphys tells them to, and at the end of the pacifist route, their happy ending is simply being with their families again. They're creepy, sure, but not truly malevolent, or are only truly dangerous should you panic and not attempt to understand them.
  • Detachment Combat: The Reaper Bird's Everyman can send its head flying at your SOUL. Actually, make that about a dozen heads at once.
  • Dual Boss: The Memoryheads are a triple boss, but in practice it's just one enemy, as you can't kill them and they're all Spared at the same time.
  • Eldritch Abomination: Although ultimately Lovecraft Lite, their powers are definitely more on this end of the fence. Their encounters play out like video game glitches, with bizarre names and strange dialogue. The Memoryheads' ACT options are your menu buttons until you use the "CALL" command. The Reaper Bird's flavor text and dialogue is multiple overlapping lines of text, and is initially only called ",". Lemon Bread's dialogue comes from 12 separate speech bubbles covering the top of the screen. If you try to ignore Endogeny, the flavor text says he appears everywhere you look, and trying to talk to the Snowdrake's Mother will often result in the dialog box describing you as doing things much more extreme than the command suggested.
  • Expy:
    • Lemon Bread has a similar name and design to Melon Bread, a boss from the Genesis game Gunstar Heroes.
    • The Memoryheads resemble Giygas.
    • As a whole, they are amalgamates of the chimeras from Mother 3.
  • Eye Scream: Snowdrake's Mother has Vegetoid faces in the place where a Snowdrake's eyes would be.
  • Final-Exam Boss: Hopefully you remember how to spare the monsters in the previous areas; you'll need to if you want to get past these guys.
  • Frankenstein's Monster: Are quite similar, such as being the result of an experiment to cheat death, being composed of multiple corpses, and their creator being horrified of what she created. Unlike the original one, however, they ultimately get a happy ending.
  • Gone Horribly Wrong: They originated as an experiment by Alphys to infuse dead monsters with Determination. To say it didn't go as planned is a gigantic understatement.
  • The Grotesque: Despite their horrific appearances, they turn out to be no more violent or evil than any other enemy you've faced throughout the game. Alphys eventually decides to quit keeping them a secret and lets them join the other monsters in the Underground, where they seem to get along peacefully enough.
  • Knight of Cerebus: Their appearance marks one of the darkest and scariest segments of the game and its backstory.
  • Lovecraft Lite: While they are quite horrific to look at and possess bizarre glitch-like abilities, they won't drive you insane when you look at them and are further disqualified from full Lovecraftian status by, well, being rather nice once you get to know them. The Memoryheads especially tell you "Come join the fun", but when you refuse they just say "Oh well" and "It's a real get together" and leave you in peace. Heck, if you decide to sleep in one of the lab's beds, an amalgamate (not pictured) will tuck you in and pat you on the head.
  • Meaningful Name: Lemon Bread is named after a type of pudding, and one of its constituent parts is Moldbygg, a gelatin monster.
  • More Teeth than the Osmond Family: Lemon Bread, whose teeth are actually made up of pieces of a Moldbygg. Their face consists of two angry eyes (which are Aaron tails) and a huge mass of gelatinous teeth. Their attack also consists of lots of teeth trying to crush your SOUL.
  • Mythology Gag: In The Halloween Hack, another one of Toby Fox's games, a trio of minibosses replacing the Krakens called the "Amalgamates" shows up in the late-game, and has the same base idea as the Amalgamates in this game (several monster parts combined to create one new monster). However, the Amalgamates in Undertale are important to the story, rather than generic baddies, though both are the last set of minibosses before the Final Boss.
  • Named by the Adaptation: Deltarune gives the names of several of the Amalgamates' before they became what they are. Snowdrake's Mother is named Crystal, one of the dogs in Endogeny was named Muttler, and Shyren's sister in Lemon Bread was named Shyra.
  • No Biological Sex: Ambiguously either played straight or Inverted. Many of them are composed of both men and women, such as Lemon Bread, who is both Shyren's sister and Aaron's brother. The game never elaborates on how (or whether) this works out.
  • No-Sell: They're completely unable to dienote : trying to attack any of them just causes random red text to quickly flash by instead of damage numbers, and the HP bar of the one you attacked extends beyond the dialog box afterwards. Fortunately, this means you can't ruin your Pacifist run by accidentally killing one. While Snowdrake's Mother does take damage from attacks normally, she's still unkillable as her health regenerates at the start of each turn.
  • One-Letter Name: In-battle, Reaper Bird's name is rendered as a single comma.
  • Our Ghosts Are Different: They are essentially undead monsters.
  • Poison Mushroom: The Memoryheads can give you a Bad Memory if you perform the Item ACT on them. It damages you for 1 HP if used, but it's a full heal at critical HP.
  • Punny Name: Endogeny. It's comprised of the parents of the Royal Guard dogs.
  • Treacherous Checkpoint: Lemon Bread, which is disguised as a Save Point until you interact with it, is the page image.
  • The Unintelligible: The Reaper Bird begins speaking with multiple dialogues overlapping over each other. It eventually separates into the individual components if you spare it. The Memoryheads can also speak in a horrible distorted screech that resembles a dial-up modem, but comes in fine through the cell phone.
  • Voice of the Legion: Lemon Bread's dialogue consists of 12 different speech bubbles cover the screen with the same dialogue.
  • Voluntary Shapeshifting: They disguise themselves in a variety of ways, such as being water in a sink (Memoryheads), a refrigerator (Snowdrake's Mother), floating particles (Endogeny), a save point (Lemon Bread), and even your '!' balloon (Reaper Bird). Save for Endogeny, the forms they take in their overworld sprites are also nothing like the ones they use in-battle.
  • Was Once a Man: All of them used to be multiple monsters. Monster bodies don't have the same physicality as human bodies, so their transplanted Determination caused their bodies to melt and fuse together instead of simply allowing their souls to persist after death.
  • Weaksauce Weakness: Endogeny is a dog, so the Stick will instantly pacify it as it does with all other dogs. If you already used your Stick, then the Hush Puppy you can get at the hotel has the same effect.
  • What Happened to the Mouse?: The Memoryheads and Reaper Bird completely disappear from the story after you deal with them in the True Lab. This is because neither of them are shown to have any family in the Underground, unlike the other three Amalgamates.
  • You Cannot Grasp the True Form: Definitely gives off these vibes, especially since their battle music takes a sample from the Trope Namer. For example, before reaching Spare conditions, Reaper Bird's name is given as a single comma, and the Memoryheads are completely incomprehensible unless communicated to through your cell phone.
  • Zero-Effort Boss: Snowdrake's Mother tries to attack, but she's so messed up that she can only fire slow projectiles that deal low damage. Sometimes, they don't even make it to the dodge window. She's also one of the easier Amalgamates to Spare.

    The Anomaly 
"It's literally you."

Thought you were just the Player Character here? Nope! Frisk and the player are implied to be separate entities in Undertale; the latter simply dictates the actions of the former. But remember that Undertale isn't a typical RPG; all of your choices will affect the game world... for better or for worse.

Depending on the interpretation, you either play as the Fallen Child (see their folder below) or yourself. Either way, this folder describes the role of the Anomaly.

  • Above Good and Evil: Since the world of Undertale is fictional and you're not, you are essentially this. However, the game will attempt to tell you that you aren't, especially in the No Mercy route.
  • Abstract Apotheosis: As noted in Sentient Cosmic Force, you’re a being only visible in consequences that happen in the timelines, you are the driving force in the world, it’s your choices and determination that replaces Frisk's. Thus (if perhaps only in the “purity of action” sense of the trope or perhaps something more literal), you are not just a determinator, you are DETERMINATION itself.
  • All-Loving Hero: It's very easy for a pacifist player to take this route.
  • Ambiguously Evil: One of the game's primary artistic purposes is opening up questions about human morality regarding how they treat circumstances where actions have supposedly no consequences. Stereotypes aside, odds are you're not actually an evil person; you just wanted to see what would happen if you killed everybody or only killed certain people. The question here is whether or not these actions actually have any true moral significance — not to the point where it's worthy of real-life reprimanding, obviously, but still enough to make the player introspect and question themself and their actions.
  • The Antichrist: In the Genocide run. You fit the archetype regardless if you’re playing as Chara or not. A figure of unending destruction who helps bring about The End of the World as We Know It.
  • At Least I Admit It: Post-genocide, should you try to play the game again, Chara will claim that you actually believe you're above consequences. There's nothing stopping you from outright admitting that's the case, and indeed, the only way to keep playing without permanently tainting the Golden Ending is to modify the save files in order to subvert the very consequences the game had in place for you.
  • As Long as There is Evil: The fact that you exist and can reset the game at any time — erasing all the progress and memories made — theoretically makes you the single most potentially evil — and unstoppable — entity in the story.
  • Ax-Crazy: Hoo boy… In the genocide run and the darker neutral runs, you are one of the biggest examples in videogame history; after all, name one character who tediously hunts down an entire country and kills them one by one, and if you choose to erase, destroys the entire gameworld. Majin Buu and Omega would be proud. Emphasis more on the ax than the crazy, as in real life you’re likely much more sane and kind, hopefully.
  • Big Bad: During a Genocide run. If you are playing as yourself and not the Fallen Child, they will take control by the end of the Genocide route, forming a Big Bad Duumvirate with you, though only for the Fallen to pull an Eviler Than Thou.
  • Big Good: You are this during a Pacifist run.
  • Blood Knight: Many a player has been convinced to do a Genocide run for the sole purpose of doing battle with Undyne the Undying and Sans, seeking a new, harder challenge.
  • Blue-and-Orange Morality: If you play through all the routes just for the sake of seeing it all, Sans in the Genocide route is the only one who comes close to considering that's why someone would do that.
  • The Corrupter:
  • Cosmic Chess Game: You're a player for once instead of a pawn; your opponent is Flowey, the only other character to use determination and who flat-out calls it a game, and also possibly Chara, though they will normally remain submissive to you.
  • Cosmic Horror Story: You can easily turn the entire game into this if you so choose. There is no character within the game, not even Flowey or the Fallen Child, who can match the sheer cruelty you can inflict upon the world. Arguably, the game is this merely by virtue of the player's relationship to it, regardless of how they actually use their power.
  • Cosmic Plaything: You become this if you sell Frisk's soul to Chara. You're allowed to start over, do pacifist, neutral, or genocide... all under the fallen human's constant supervision. Though you can, of course, completely avert this at your own discretion if you decide to modify the saving files.
  • The Dark Side: You are the Dark Side, feeding Chara power and corrupting them into evil and being the Antichrist to your Satanic Archetype at the same time. (Only in the genocide run or when you kill somebody, really.)
  • Determinator: You have to be to get one of the true endings, or even make it to the end after all the deaths you’ll get; determination and the resolve to achieve what you want is one of the game’s main themes, and it’s heavily encouraged in players to match Frisk and the Fallen Child.
  • Dragon-in-Chief: Depending on how you see Chara and their relationship with you, either you are this to them or they are this to you, or you're on equal terms.
    • It's the Fallen Child's LOVE and stats Frisk (and you) are using.
    • It's you who actually does all the work, dodges the attacks, etc., with Chara simply providing the muscle and information.
  • Dramatically Missing the Point: Plenty of players have gloated about how they've outsmarted Chara by, after completing a Genocide Run, editing the game files in order to give themselves their Golden Ending back, thus proving that they don't "think" they are above consequences, they are above consequences... all while completely overlooking the fact that them doing this proves that they acted in exactly the way Chara has predicted them to: refusing to accept any kind of lasting negative consequences for what their own actions did to the game. In fact, answering Chara's accusation that you believe you're above consequences with a blunt "yes" simply has them agreeing with you.
  • The Dreaded: It's perfectly possible to be this even though everyone will think you’re Frisk, but well, basically the entire underground will fear you.
  • Eldritch Abomination: A being beyond comprehension, the same species as the creator of the world, utterly beyond punishment and capable of altering reality with ease. Powers include possessing Frisk, returning lost beings back into existence, resetting the world and, yes, even undoing what cannot be undone. No one can understand why such a being would do what it does.
  • Empowered Badass Normal: A normal human, armed solely with your determination and your skills as a player and possibly a hacker, given a computer, an Undertale program and Time Master and Demonic Possession powers over Frisk and the game world. That's all you need to fight and defeat/conquer even the greatest opponents and challenges the game has to offer, such as Sans and Undyne the Undying.
  • Eviler Than Thou: When it comes to Flowey and Chara in a Genocide route:
    • By the end of the route, Both you and Chara turn on Flowey and by the end chop him to pieces. A short conversation later, Chara pulls this trope on you.
    • Invoking this is about the only way you can get a semblance of victory over the Fallen Child, baffling them with your sheer depravity.
    • Have you done a Genocide Run but don't want to sell your SOUL? Don't even bother to open the game again after Chara crashes it. Just straight up uninstall it right then and there (And if you ever want to play it again, you may reinstall it). If you do that you can pull this trope on them.
  • Evil Is Not a Toy:
  • Expendable Alternate Universe: Want to keep playing the game, even after getting the Golden Ending, and Flowey asks you nicely not to? Just copy your save files! Everyone gets to keep their happy ending, while you still get to have fun...
  • Face–Heel Turn: Any player who gets the True Pacifist ending, then resets and starts a Genocide run pulls one. For a while, you still have a chance to turn back.note 
  • Fighting a Shadow: The main reason why no one can hurt you, no matter how badly they want to. You’re in Real Life, a literal higher plane of existence, using Frisk as your avatar in the game world; how are they supposed to reach you, much less do you harm?
  • From Nobody to Nightmare: If you choose to take the No Mercy run, you go from attacking common monsters to mutilating bosses in one hit to destroying the world with help from the fallen human.
  • A God Am I: Invoked. Flowey will call you out on your attempts to shape destiny.
  • Greater-Scope Paragon: In a meta sense. Since Frisk is the main character and Sans and Toriel are both technically the Big Good, that technically makes you the greater scope paragon of the entire game, since you're technically responsible for most of what Frisk does in the story... assuming that you aren't going for a genocide run, of course. That being said, on the flipside...
  • Greater-Scope Villain: ...Also in a meta sense. With the Narrator Chara theory gaining more and more supporters, the Undertale fandom in general has come to the consensus that it's not Chara's fault — it's yours for making Frisk do the genocide route and causing the world's destruction. These days, you'll find much more YouTube comments along the lines of "Chara is evil in a Genocide Run, but so are you and/or you made Chara that way!" than the latter. Heck, there's even a YouTube video out there with the song "When You're Evil" regarding the player, not Chara. Given that there's no Word of God on the issue currently though, it's all open to interpretation, much like many other aspects of Undertale. This trope only applies if you're going for a No Mercy/Genocide run.
  • The Hedonist: Sans in a No Mercy run accuses the Anomaly of never being happy, always wanting more.
  • Heel–Face Door-Slam: Interestingly enough, this only ever happens to you, the player, in the aftermath of a genocide playthrough. Once you've done this, and sold your soul to recreate the world, you will never have a true Golden Ending again without cheating. For everyone else, though, this trope is averted and characters who have done terrible things will be forgiven, since, well, that's what the game is about. Alphys, who's responsible for innocent monsters being turned into the molten-together and horribly disfigured Amalgamates, gets fired from her job when she tells the truth, but since monsterkind is about to leave the underground anyway, this won't actually be a bother — and her friends continue to be by her side anyway. Asgore, who has the blood of six human children on his hands, is still a respected leader. And in most cases, you're the one to show mercy, like with Undyne or Flowey.
  • Heel–Face Revolving Door: A player who goes through several runs choosing a different route each time is essentially this.
  • Heel–Face Turn:
    • The game allows a player on the Genocide path to step off it up until the Mettaton NEO fight. When Papyrus, for example, offers to Spare you, it's a genuine offer with no strings attached, and will revert your game to a Neutral one. Sans' offering, on the other hand, is not.
    • It's possible for the trope to still be played straight after the player accepts Sans' false offer of mercy, if the player takes the skeleton's words to heart and RESETS after getting dunked on. Of course, this depends entirely on you.
  • He Who Fights Monsters: Literally on the more malicious runs.
  • Hijacking Cthulhu: From the moment you start Undertale, you've unwittingly seized the power to SAVE and RESET away from Flowey/Asriel, and he really doesn't take kindly to this.
  • Humans Are Cthulhu: Everything in the game world is up for your own amusement. There's absolutely nothing the entities within can do to harm you. Even when Chara pulls an Eviler Than Thou to screw you over beyond the fourth wall after a No Mercy run, you can screw them over beyond even that by actively editing the game's codes. Sufficiently informed, you can manipulate anything in the game.
  • Humans Are the Real Monsters: Should you decide to go full Genocide or kill almost everyone in a more neutral route.
  • Humanoid Abomination: In Undertale, the line between Chara, Frisk, and the player gets extremely blurry, so their “inhuman” descriptions in the Genocide Route should probably be taken to include you. If that is not eldritch enough, see the Eldritch Abomination entry, so yeah, you fit straight here, especially in No Mercy; has it even occurred to you that maybe, just maybe, Chara is able to take your (or Frisk's) SOUL because you turned demonic and not them.
  • Incorruptible Pure Pureness: The player who chooses to go full pacifist, ensuring the happiest of endings, and never play the game ever again (or watch anyone else play the worst endings), achieves this trope.
  • Invincible Hero: If you're truly Determined to give as many characters as possible their happy ending, or to slaughter the entire Underground, then there's nothing anyone can do to stop you; Flowey will become just a minor irritation, as will all your possible deaths. In a greater sense, you yourself are literally invincible, as you exist in a different dimension than the characters.
  • Invincible Villain: There is also nothing the characters can do to stop you from doing a Genocide run, aside from trying to talk you out of it or hoping you'll get bored and give up. With your Determination, every defeat is just a setback. The only one you can't beat, without manually altering game files, is the Fallen Child after you've sold Frisk's soul to them.
  • It Amused Me: During the final battle of the Genocide route, Sans will start speculating on your motivation for all the evil things you've committed. At first he considers that you might simply enjoy killing things, but then brushes the idea off as ridiculous, saying that "you're the kind of person who won't EVER be happy". He then goes on to accuse of you of this trope, saying that you're not even motivated by good or evil anymore, you're just doing this because you can. And because you have that ability, and are seemingly above consequences because of your ability to SAVE, you just can't help yourself. It's a gamer's natural desire to seek out and accomplish everything in a game, after all.
  • I Want My Beloved to Be Happy: If you listen to Flowey and choose to abstain from a True Reset after getting the Golden Ending, letting the characters you've grown to know and love happily live out the rest of their lives without you. Believe it or not, quite a few fans will admit to having done this.
  • Karma Houdini: On normal playthroughs, this is averted. If you attempt to play a True Pacifist run after beating the Genocide path, you'll quickly find that this actually leads to the worst possible ending, and you can never again get the best ending, dooming all the innocent people in the game to a grisly fate, forever. To legitimately engineer this trope, you have to manually erase all records of finishing the Genocide ending from the save files.
  • Knight of Cerebus: In a Genocide run.
  • Lack of Empathy: To get the Genocide ending, not attaching yourself to the characters in the game is pretty much a given necessity.
  • Lovecraft Lite: Despite all those horrifying things that you can do in the game to this world and its people, nothing can make you do them. It's possible to achieve the Golden Ending without killing anyone... and even if you want to replay the game, you can always abstain from the No Mercy route and achieve the Golden Ending again.
  • Mistaken Identity:
    • If you believe you are playing as yourself and not the Fallen Child , then any time Flowey addresses you as the Fallen will count as this.
    • A subtle example in Sans. He seems to be the only character (aside from possibly the Fallen) who confirmably knows that you even exist — but while he correctly identifies you on a Genocide run as the cause of the latest resets, he doesn't seem to realize that you haven't always been the one resetting the timeline. Flowey's speech a few rooms earlier gives the impression that his reign as resetter was a Time Abyss; most likely, he was responsible for far more loops than the player ever could be. Sans never seems to realize this. However, it's not clear whether the "anomaly" in question is Frisk or the player since it's unclear who's truly in control of all resets.
  • My God, What Have I Done?: The game tries very, very hard to evoke this feeling out of you the entire time you play the Genocide route, and during worse Neutral endings, in the hopes you'll Reset.
  • No Challenge Equals No Satisfaction: It's the aspect about you that Sans fears most. You're neither doing anything good because it's the right thing to do, nor anything evil for sick pleasure — but simply because it's a challenge. And because you can achieve it, you may feel required to.
  • No Kill Like Overkill: Your damage becomes ridiculously excessive in the Genocide route.
  • Nominal Hero: You don't actually have to feel sympathy for the inhabitants of the underground, but can still go through with the Pacifist ending because you find it to be an obligation. (Which it is, if you want the final ending.)
  • Omnicidal Maniac: In a Genocide run, the Anomaly decides to kill every single living creature it can, despite the fact that none of its victims can even begin to hurt the Anomaly.
  • Omniscient Morality License: Since you have the ability to go back and fix things whenever you want, just like any other video game, you essentially have omniscient control over the game's universe and may be tempted to succumb to this. If you do, you'll be faced with quite a bit of harsh deconstruction.
    Sans: sometimes... you act like you know what's gonna happen. like you've already experienced it all before. this is an odd thing to say, but... if you have some sort of special power... isn't it your responsibility to do the right thing?
    Sans: heh. well, that's your viewpoint. i won't judge you for it. ... Y o u d i r t y b r o t h e r k i l l e r.
  • Outside-Context Problem: Your ability to SAVE and RESET are extremely rare abilities in the game's setting, but certain characters can use them. Your ability to alter the game's data, however, is something none of them could ever replicate. On another level, you're a being from outside the universe that none of the characters could have ever predicted would have shown up and whose nature is inherently different from all of them. They can do nothing to stop you no matter what you do, as you operate on completely different rules than they do.
  • Pay Evil unto Evil: You can take the game's story and characters 100% seriously and still choose to kill some of the more aggressive monsters if you think they deserve it.
  • The Perfectionist: If you're trying to do a specific playthrough, yet reset or save scum after every screw-up. Flowey may even call you out on it depending on the circumstances.
  • Person of Mass Destruction: As Sans describes it, a Genocide path will not bring you any kind of satisfaction, you'll just keep consuming timeline after timeline.
  • Player and Protagonist Integration: You start controlling Frisk as a Heroic Mime, and in most playthroughs, that is all that you are. By the end of each route, it's implied you're separate entities: either you are playing as the Fallen controlling Frisk,or as yourself.
  • Reality Warper: You can delete and edit the game’s files, which clearly makes you this in a meta way, and, as said everywhere else, Undertale is a very meta game on purpose — then there's the ability to reset...
  • Redemption Equals Death: If you take Sans up on his offer of friendship at the end of the No Mercy run, he'll kill you and tell you that if you were sincere about being friends, you'll never come back. Though this is an interesting twist on the trope because Sans is well aware that you're unkillable you can't be Killed Off for Real because you can control time, so his saying that doesn't mean "stay dead", he's telling you "reset and be a better person".
  • Screw the Rules, I Have Supernatural Powers!: You have the power to SAVE, and reset, time itself, if you so choose. However you're not the only character who can handle that raw kind of power; Asriel and Chara will try to wrestle it back from you, and with the latter it's for keeps. Though the fact that you can go a step beyond and edit the files of the game means that your powers will (in a meta sense, anyway) always outclass Chara's.
  • Sentient Cosmic Force: An interpretation, as you’re a being only visible in consequences that happen in the timeline; you are the driving force in the world. It could be said that you are Frisk/Chara's DETERMINATION.
  • Set Right What Once Went Wrong: Should you ever have a change of heart during the Genocide route, undoing your mistakes via a Reset is always an option. Once the route has been brought to completion and the entire world has been erased, however, you'll have no choice but to live with your wrongdoing. A complete inverse of this is the player who decides to do a genocide run after fulfilling true pacifist.
  • Super-Powered Evil Side: For Frisk, especially when you start killing literally everyone against Frisk's will; remember, Frisk is just a little kid who most likely would not want to hunt down and kill every single monster, and even if they did, being just a child they probably wouldn't have been able even if they tried. You’re the one fighting, the one dodging, and the one killing. In pacifist, you’re a much more benevolent Super-Powered Alter Ego. In a very confusing double wammy, should you interpret Chara's speech as literal, Chara by the Genocide ending could be interpreted to be yours, an embodiment of everything destructive you've ever done in videogames given life by your own hands.
  • Space Time Eater: A sentient time-space anomaly that can consume as many timelines as it wants.
  • Spanner in the Works: The player character can be this, most obviously in a Pacifist Run. Regardless of the run, you undermine each boss' plans to either keep you as a guest or prisoner, kill you, and take your soul to the king or for selfish purposes, or stop you from destroying the world. In fact, once you become friends with everyone, you then undermine Asriel's plan to remake the world and start afresh because you remember each of your friends' likes and dislikes while they are trapped inside Asriel.
  • Stupid Evil: Although there are some interesting things to be found within, like character development, very few people consider the Genocide Route even remotely as enjoyable as the Pacifist route, for a myriad of reasons. It's significantly harder, for example, to the point where the final boss is very clearly designed to be as unfairly frustrating as possible, and the humor and charm is all but nonexistent. As such, many would consider it an unnecessarily exhausting, unsatisfying, and emotionally draining journey to partake in, and Sans, the only character who's aware of your existence, clearly agrees. When analyzing you psychologically at the end of his boss fight, he comes to the conclusion that the only reason you're still here is because you can be.
    Sans: and because you "can"... "have to".
  • Symbiotic Possession: The player controls most of Frisk's actions, but a more benevolent player acts closely to Frisk's desires anyway. As Frisk is a child, they arguably couldn't complete their quest without you, even if they could use determination on their own.
  • Time Master: In this game, resetting and reloading are real, In-universe things.
  • Talk to the Fist: On the Genocide path, you often walk up to the major characters and one-hit-kill them without a word.
  • Technical Pacifist: Possible if your main method of Sparing is to beat the opponent until they have low health, though the fact that monsters take more damage the lower their health is makes this impractical. You can also engage in multiple Kick the Dog moments via dialogue options without having any impact on a True Pacifist run.
  • Tom the Dark Lord: You are most likely going to be this in a Genocide run. Why would your own name be scary?
  • Ultimate Evil: You can become this if you try hard enough. The Fallen will attempt to take this title from you at the end of the first No Mercy run, but if you're cruel enough over subsequent runs, they will eventually give up on out-eviling you. Notably, the Fallen is outright confused at how you could possibly be eviler then them even while admitting it's true. Also true in a more specific sense as, being the player, of course you don't show up in the game.
  • The Unfettered: Undertale is heavy on meta commentary about how your actions can affect the game's world for the worse, what might be your reasons for pursuing bad outcomes, and even how much you're willing to cheat to take what you want from the game. If the worst comes to pass, Sans accuses you of having done it all just because you could and the Fallen Child outright calls you the sort of person who thinks themselves to be above consequences and who acts on perverted feelings for the game's setting. You can prove that and assert your power over the game by erasing the records of your deal with the fallen human. On the other hand, there are plenty of people out there who have resisted the temptation of doing a Genocide run and who even hesitate in doing a True Reset after listening to Flowey's last request. However, the game does not spare calling out those who may have been pacifists themselves, but watched someone else take the Genocide route instead.
  • Vile Villain, Saccharine Show: One of three, along with Flowey and the Fallen Child, as you are the one who plays the No Mercy run, which makes you the biggest Knight of Cerebus; interestingly, you have the choice to be the reverse and make the game happy and quirky.
  • Villainous BSoD: A very, very common reaction — the intended reaction, even — for those who play the Genocide route, especially those who had no idea what they were getting into. Some choose to reset and undo their mistakes at that point, while others choose to grit their teeth and press on anyway.
  • Well-Intentioned Extremist: You can invoke this (especially if this isn't your first playthrough) as an excuse to kill every boss monster while sparing the citizens. This results in the Annoying Dog taking over the throne, and arguably the second-best ending in the game right after True Pacifist. Even Sans would say thanks at the end of it, despite him being rightfully angry at you for killing his brother earlier. This can also apply to players who started out sparing the monsters but killed at least a few of the later encounters because they just couldn't find out how or they didn't find them to be worth the effort.
  • What the Hell, Hero?: Beating the game on the True Pacifist Run and rebooting the game gets you a lecture from Flowey of all characters, calling you out on taking the characters' happy ending away from them because you were bored, and referring to you as a possibly worse person than him.
  • Wrong Context Magic: Even if it's only a few people, there are those who know about the power of determination and resetting. What they don't know about is the Anomaly's power to alter the game's data. Even Chara's attempts to trap them with the consequences of the Genocide run are nothing in the face of this.
  • Wrong Genre Savvy:
    • The first boss asks you to prove that you're strong enough to survive outside. Anyone familiar with Role-Playing Games in general would try to beat Toriel to an inch of her life before Sparing her. The encounter's designed so that she's instantly killed when her health reaches 30%, and you're guaranteed to feel like a scumbag afterwards.
      • Interestingly, on a Full Pacifist Route the game does this to you again with Asgore but in reverse. Asgore's boss fight plays the RPG trope straight, you HAVE to fight and beat him within an inch of his life to Spare him but by then you've played almost the entire length of the game having adapted to its new rules. You end up frustrating yourself trying to find a hidden (non-existant) trigger for a non-violent Mercy Condition just as you've done all game for every other monster. Wrong Wrong Genre Savvy?
    • The game itself is very meta, and if you think you can just save and load as you please to see what would happen if you do this or that, you will be in for a nasty surprise.
  • Yandere: You can be a platonic version of this if you reset a True Pacifist ending, taking away a happy ending in order to spend more time with characters you've grown to love.
  • Yank the Dog's Chain: How the aforementioned permanent Heel–Face Door-Slam manifests. Even if you do everything right and get a Pacifist Ending, in the end, the Fallen Child is revealed to still have Frisk's soul, after which they'll take control and possibly starting killing again, anyway.
  • Your Approval Fills Me with Shame: Just like My God, What Have I Done? trope above, the game evokes this trope to the player at its hardest. When Flowey or Chara/the fallen human congratulates you, the player (and/or Frisk) for killing Asgore and/or Flowey himself in the Neutral route on the former, and completing the Genocide/No Mercy route on the latter.

    Asriel Dreemurr
It's me, your best friend.
Absolute GOD of Hyperdeath 
Final Form 

The deceased (and later reincarnated) Crown Prince of the Underground. His mind was resurrected within a flower that had Determination injected into it, but without a SOUL and the ability to feel compassion, he was twisted over time into the being calling itself Flowey.

  • Abnormal Limb Rotation Range: When using his Chaos Saber attack, he rotates his head 360 degrees, vertically before delivering the last slash.
  • Amazing Technicolor Battlefield: In his powered-up form, he will wait for the music to swell before turning the background into a trippy rainbow tunnel.
  • Animesque: In the final battle, he crosses the Bishōnen Line, gives himself an over-the-top Large Ham Boss Subtitle, calls his attacks, and the attacks themselves are visually stunning and look like complete overkill. It's actually a kind of sad twist on this trope by reminding you that under that almost demonic looking exterior, he's just an eight-year old fighting like how he would have seen in a cartoon or read in a comic.
  • The Anti-Nihilist: In contrast to Flowey, once redeemed, Asriel expresses the opinion that while the world can be a dark place filled with Floweys, what should be strived for is an existence where nobody kills and nobody is killed.
  • Anti-Villain: Really, he is just a child who was betrayed by his adoptive sibling, whom he still loves and misses. He just doesn't want to be alone anymore.
  • Arm Cannon: One set of his attacks in the first stage of his boss fight has him morph one of his arms into a gun.
  • Baleful Polymorph: Alphys' experiments on monster souls and Determination led to him being inadvertently reincarnated as a soulless flower known as "Flowey." In the Genocide route, Flowey recounts how horrifying it was when he awakened to find that he couldn't feel any of his limbs; in the True Pacifist route, when he regains his original form as Asriel, the first thing he does is test his newly-regained arms, silently laugh to himself, and mention how he was so tired of being a flower.
  • Became Their Own Antithesis: The All-Loving Hero who died because he refused to lift a finger in self-defense against his people's ancestral enemy was twisted by forces beyond his control into an Omnicidal Maniac. And when he returns to his old self, he's soon paralyzed by the accumulated guilt his Flowey form had suppressed all those years.
  • Berserker Tears: Once you save the souls of all your closest friends from within him, you are given the opportunity to save him. Soon, he starts to break down. He'll begin to sob while begging you to let him win, that you and he will be happy together, eventually bursting into a bawling scream as he fires a point-blank Death Ray at Frisk.
  • Bishōnen Line: His final boss form is far more powerful than the boss form he assumed as Flowey in the Neutral run, and is also much more anthropomorphic, simply being a grown up version of himself with slightly demonic features. This ends up getting played with a bit upon his transformation into his final form, which is strange and mechanical-looking, but is still nowhere near the abomination Flowey became.
  • Black Eyes of Evil: In his Bishōnen Line form, his sclera are black with narrowed white pupils, contrasting both of his parents, who have standard white sclera and black pupils.
  • Boss Subtitles: He's the sole individual who actually has a boss subtitle during his introduction, which makes sense, given that he's a little kid given god-power, and everything he does in this form is his idea of Rule of Cool.
  • Calling Your Attacks: During the first phase of his fight, the text box will announce which attack he'll use (Star Blazing, Shocker Breaker, Chaos Sabers, and Chaos Buster). The same attack types even have upgraded versions with different names he uses halfway through (Galacta Blazing, Shocker Breaker II, Chaos Slicer, and Chaos Blaster). Funnily enough, Asriel isn't actually saying the attacks in his text speech balloons; it's the narrator describing them. This trope still applies, though, because it's clear that at least someone is describing them.
  • Came Back Wrong: As is said early in the game, when a monster's ashes are scattered onto their favorite thing, their essence lives on, permeates it, even without a SOUL. Unfortunately for Alphys, she had no idea that the flower she'd chosen to bring to life through Determination was carrying Asriel within it. Thus, the product was a soulless vessel carrying the will and intelligence of their crown prince, with no capacity for any kind of love: Flowey.
  • Catharsis Factor: In-Universe, Asriel experiences this at the end of the True Pacifist route. Part of his jaded views as Flowey stemmed from the fact that he blamed himself for his and Chara's deaths and their plan failing, since his Fighting from the Inside to prevent Chara from killing the human villagers led to the humans killing them instead due to a misunderstanding. At the end of the game, Asriel is finally able to let go of his guilt and regret after meeting Frisk makes him realize that Chara wasn't as great of a person as Asriel had been trying to convince himself they were, and that he did the right thing by preventing Chara from killing them.
  • The Chosen One: In the True Pacifist route, he becomes the Angel spoken of in the Delta Rune's prophecy; he has seen the surface before, having gone there in his attempt to return Chara's body, and upon returning to his true form and being redeemed, he uses his power to shatter the barrier.
  • Clipped-Wing Angel: He's far less aggressive and 'unfair' than Photoshop Flowey, and despite being far more powerful, his attacks are likely a little easier to deal with (even discounting the player getting permanent Auto-Revive for the fight). This makes perfect sense, really, as absorbing all those love-filled souls restored his conscience, and he's clearly struggling to sustain the hatred powering his attacks.
  • Crucified Hero Shot: After you save him and get him down to his normal child form, he releases the souls of the monsters and the Fallen Children this way. This also shatters the barrier.
  • Determinator: Manages to force control from Chara and run away from the humans, even while being murdered. As a reminder, Chara is a borderline eldritch abomination who usurps the player (aka God) in the No Mercy run.
  • Even Bad Men Love Their Mamas: His base-power form is borrowed from Toriel's appearance — same height and width, though he wears a tabard with the Delta Rune on it, and has horns that curl outward, as well as the aforementioned Black Eyes of Evil.
  • Even Evil Has Loved Ones: It's the driving force behind his villainy. He simply cannot let go of the Fallen Child.
  • Fallen Hero: In life, he was selfless enough to choose death over murder. After his reincarnation, he'd come to regret his sacrifice and, as a result, adopt a worldview antithetical to it.
  • Fate Worse than Death: No matter what choices you make, you can't save Asriel and bring him to the surface with you. He is either stuck in the underground as Flowey for the rest of his reincarnated life in a True Pacifist run with no one other than Frisk knowing that he was ever brought back, or has that vessel mercilessly hacked to pieces in a Genocide run (presumably, either Cessation of Existence or And I Must Scream apply for the latter).
  • Fighting from the Inside: Tragically, while this doesn't happen when he's Flowey, when spoken to in the True Pacifist's epilogue he states that the Fallen Child wanted to use their combined power to annihilate the humans living in their hometown (probably to defend themselves). Asriel resisted, and they were mortally wounded as a result.
  • Final-Exam Boss: Rescuing the Lost Souls involves fighting them in the Red (Toriel and Asgore), Yellow (Dr. Alphys), Green (Undyne), and Blue (Sans and Papyrus) heart modes.
  • Final First Hug: With Frisk, if the player chooses to comfort him at the end of the Pacifist Run.
    Asriel: Ha... ha... I don't want to let go.
  • Foil: As a boss, he's one to Sans, who's fought at the end of the polar opposite route of the one that Asriel is found in. Despite being labeled as having infinite ATK and DEF, Asriel's attacks aren't too difficult and only deal a finite amount of damage, plus you literally can't lose. Sans, on the other hand, is claimed to be "the easiest enemy", and despite having only 1 Attack and 1 Defense, he packs brutally hard attacks intended to wreck you in the most unfair ways possible. You fight Asriel to get back all the souls he absorbed and automatically revive when killed out of sheer determination to save them, while Sans fights you to protect what's left of monsterkind by kicking your ass until you give up. Story-wise, he tries to manipulate you into a "kill-or-be-killed" mentality as Flowey, while Sans tries to befriend you to prevent such a thing from happening.
  • Godhood Seeker: His ultimate plan, both as Flowey in the Neutral route, and as his resurrected self in the True Pacifist route. He thinks he and Chara will become gods in the Genocide route as well. He's wrong.
  • Grand Theft Me: A victim. Asriel absorbs Chara's soul in the backstory, acquiring a new powerful body, but much to his horror, finds out that Chara also has control over that body and wants to attack the people of their home village with their newfound power. It takes every ounce of willpower to resist the Fallen Child's will.
  • The Greatest Story Never Told: At no point in a Pacifist Run (the only run where Asriel can actually come into being) can he be reunited with his parents, or even have the fact he exists again be known to any other character. After he redeems himself, he purposely puts himself out of sight from anyone who knew him, knowing the joy of reuniting with his loved ones would be tragically short-lived, given that he still lacks his own soul and will eventually revert back to a souless flower.
  • Heel–Face Turn: Asriel pulls this at the end of the True Ending, having regained his ability to feel compassion (at least temporarily).
  • Heel Realization: Asriel during his boss fight with you, when you reawaken the monster souls he has absorbed and he starts to regain his compassion. After he turns back into Flowey, he uses this trope as the reason why the player should erase his memories too, should they decide to start a new game — he feels so bad about how terrible he was to everyone around him that he doesn't think he'd be able to play the same role again.
  • Hoist by His Own Petard: Throughout the game, especially in a Pacifist run, he repeatedly exploits the trust and compassion of the people around him in order to get all monster and human souls in one room and devour them simultaneously. When he finally does, he gains the power of a god — but also regains his own compassion, and Frisk's pacifism turns him from a sociopathic maniac to a sobbing wreck who can't bring himself to hurt people anymore. And if you do the True Reset, he points out you're even worse than he is because you're enacting the very same insane, evil plan he was trying to do after even he himself had let it go.
  • Hopeless Boss Fight: Just like when you face him as Flowey, he tries several times to convince Frisk that they are completely helpless. In actuality, Frisk is this for Asriel. No matter what Asriel does, or how many times Frisk is brought down to 0 HP, Frisk's determination keeps them going.
  • HP to 1: His final beam attack will reduce your life meter to 0.0000000001/20 HP — one ten-billionth of a hit point. Subverted, however. That's not what it's intended to do. It's supposed to kill. Frisk is just that determined to stay alive.
    • If you get hit by his powered-up form's final attack, the Hyper Goner, you instantly drop to 1 HP.
  • I Hate Past Me: In the epilogue of the True Pacifist playthrough, he expresses sincere remorse for his actions as Flowey, to the point where he asks Frisk to consider his two forms to be separate individuals should they meet again after he's reverted to being Flowey.
    Asriel: Let's be honest. I did some weird stuff as a flower.
  • I Just Want to Have Friends: The Fallen Child was the closest thing Asriel had to a friend, with the monsters suggesting that Asriel and the Fallen Child were like siblings. Asriel simply cannot let go of his memories of them, to the point of projecting the Fallen Child onto Frisk; he just wants to see his friend/sibling again that badly. This is part of why his Flowey persona is so elated to see the similarities between the two at the start of a Genocide route.
  • It's All My Fault: He explains that his "Kill or be Killed" outlook as Flowey came from him blaming himself for preventing the Fallen Child from attacking the humans, which resulted in them dying and Asriel being reborn as a flower. His jaded belief that "love and compassion" only cause pain and suffering is due to this as well, as he refuses to believe that his beloved Chara is at fault and blames his decision to spare the human village instead, as the cause of everything that came after and the pain he and his loved ones experienced because of it. Luckily, he finally gets over this at the end of the True Pacifist run, realizing that he did the right thing and accepting that Chara "wasn't really the best person".
  • Large Ham Title: After the music swells, the "Check" command declares Asriel "The Absolute GOD of Hyperdeath!"
  • Leitmotif: Your Best Friend and Memory, which is further reprised in Undertale and His Theme. For his boss fight, he gets Hopes and Dreams, Burn in Despair!, and SAVE the World, in that order.
  • Light Is Not Good: His hyperdeath form looks like an angel and has rainbow light attacks.
  • Like Father, Like Son: There is at least some hints of it. Most notably in how he names himself "Flowey the Flower" after having been reincarnated as said flower. He clearly has inherited his father's penchant for coming up with lame names.
  • Living on Borrowed Time: In the Playable Epilogue of the True Pacifist, he's restored to his true form, but says that without a soul, he'll eventually return to being Flowey.
  • Luke, You Are My Father: Odd example. Neither Toriel nor Asgore find out that Flowey is Asriel, but Frisk does.
  • Many Spirits Inside of One: His final form, comprised of every soul in the underworld.
  • Meaningful Echo: After you go back to the first screen of the game and talk to him, he'll end the conversation with "Don't you have anything better to do?"
  • Meaningful Name: His name is chock-full of meaning:
    • Asriel's name shares the Theme Naming of angels and means 'Prince of God' in Hebrew, or 'One who helps God'.
    • "Asriel" is an amalgamation of Asgore and Toriel. As mentioned before, Asgore is really bad at naming things.
    • If you rearrange the letters in "Asriel Dreemurr", you get "Serial Murderer".
  • Morality Pet: It's pretty clear that whatever Chara was really like, they had some level of fondness for Asriel, possibly at the exclusion of everyone else. Whether this fondness was shallow and ultimately unimportant to them in the grand scheme of things, genuinely deep and familial, or anywhere in between is still hotly up for debate.
  • Morphic Resonance: Flowey and Asriel share the exact same color pallet: green, yellow, white, and black. Asriel has a fifth color in his overworld sprite, purple, but otherwise uses the exact same colors. Also, at the end of the Genocide route, Flowey reveals that he can still mimick Asriel's real face and voice, whipping them out only as a last ditch attempt to stop the player from killing him, which still fails.
  • Names To Run Away From Very Fast:
    • Asriel is also a reference to Azrael, the name of the Archangel of Death. In one of his forms, Azrael has four faces and four thousand wings, and his whole body consists of eyes and tongues; the number thereof corresponds to the number of people inhabiting the Earth. Sound familiar?. He will be the last to die, recording and erasing, constantly in a large book the names of men at birth and death, respectively, paralleling his control of the game overs as Flowey. His name is also an anagram that spells Serial Murderer.
    • The Absolute GOD of Hyperdeath is something that Asriel (and the narrator) calls himself during his fight.
  • Nigh Invulnerable: You cannot harm him in the final battle. Asriel becomes everything the human ancestors feared. Thank goodness, like all monsters, he regains his love and compassion, or else you'd be screwed.
  • No Good Deed Goes Unpunished: All he wanted to do was return the Fallen Child's body to their village out of respect. The humans thought he killed the Fallen Child, and attacked him, leading to his own death.
  • Non-Standard Character Design: During the fight against Asriel, the screen suddenly starts displaying rainbow patterns in the background, and his name is listed in dancing rainbow text in the ACT menu.
  • Older Alter Ego: When he fights you, he ages himself up from a child to what looks to be a young adult. He reverts back to his child form once he loses the will to fight, though he briefly assumes his older form again for a gag during the True Pacifist credits.
  • One-Winged Angel: After absorbing the Fallen's SOUL, Asriel was stated to have undergone a transformation into a powerful form, which is presumably the same form he takes during the first stage of his boss fight and simply resembles an adult version of his species, similar to his parents. His final form also qualifies, as it resembles a winged, demonic version of himself.
  • Only Friend: Chara. The entire reason he's putting Frisk through a fight is because he thinks they are Chara, and if the player gets their "happy ending", "Chara" will leave them forever. Whether his fears are founded depends on if the player subscribes to the "Chara is the Narrator All Along" theory or if they've cleared a Genocide route previously, though the second case could be a blessing in disguise...
  • Our Ghosts Are Different: Unlike the Blook family, Asriel is dead and only persists due to having been accidentally revived as Flowey. Once he collects all the SOULs in the Underground, he gains enough power to recreate himself, but chooses to restore everyone instead.
  • Physical God: In his Boss Monster form, he not only has the power of six human SOULs, but of all the other monsters the Child has encountered except Napstablook, making him even more powerful than Photoshop Flowey.
  • Platonic Declaration of Love: While the word "love" is not used, this is how his boss fight ends. Asriel starts by saying the player (who he's projecting his feelings about Chara onto) is special and the only one who is still fun to play with, but then isn't satisfied until he adds how much he genuinely cares about them.
  • Playing with Fire: One of his attacks, shared with both his parents, is a storm of fireballs. Also, like his mother, towards the end of the fight, the fireballs will intentionally start avoiding the player's SOUL.
  • Please Don't Leave Me: Said almost verbatim during the final fight against him on the pacifist route and combines this with Berserker Tears.
  • Portmanteau: Asgore + Toriel = Asriel. Asgore really is bad at naming things.
  • Post-Final Boss: After the intense fight with Photoshop Flowey, the Pacifist route's final battle, Asriel Dreemurr, is impossible to lose since you revive each time you die, and you can "dream" for as many healing items as needed. His fight serves less as one final challenge and more as an interactive cutscene which ends the game's story on a high note.
  • Power-Upgrading Deformation: The Pacifist final boss goes from flower to formerly-dead little boy into something made of edge but still recognizable, ending up as half-abstract goat-machine abomination.
  • Prone to Tears: Particularly in his child form.
    Asriel: I always was a crybaby, wasn't I, Chara?
  • Redemption Equals Death: A downplayed example. He considers Flowey to be a completely different being, so by releasing all the souls to destroy the barrier, he knowingly goes through Death of Personality.
  • Reincarnation: After an unknown length of time passes after his death, Alphys's experiments with determination brought him back to life in Flowey's form.
  • Ridiculously Cute Critter: His original child form is this to many fans of the game.
  • Rule of Cool: The form he takes in his adult form during his boss battle is this to a T; his attacks and his appearance all incorporate things he really loves—stars, prismatic color schemes, and (as mentioned before) his mom. Deep down, he's still just a little boy with a big heart, who just wants to be with his best friend and family again. *Sniff*.
  • Significant Anagram: His name is an anagram of "Serial Murderer", of all things. Not so appropriate for Asriel himself, but it fits Flowey to a T.
  • Slap-on-the-Wrist Nuke: Asriel Dreemurr has "Hyper Goner" for the ultimate attack of his powered-up form, where the dodging space expands to cover the entire screen (including the status bar). He forms a black hole that sucks you and several damaging diamond shaped projectiles in towards it. Despite the incredible animation, it can only leave you at 1 HP. After that, he transforms into his final form, where you're unable to use items at first and you're forced to dodge several tricky volleys of projectiles.
  • Spanner in the Works: In the backstory, Asriel in the Fallen Child's Thanatos Gambit. The plan was to go above after Asriel absorbed the Fallen's soul, collect at least six more human souls, and free everyone Underground. When humans attacked with Asriel being Mistaken for Murderer for holding his sibling's human body, Asriel refused to lash out. Instead, a wounded Asriel returned to the Underground and died from his injuries, accomplishing nothing.
  • Suddenly SHOUTING!: If you take his Boss Subtitles as this, especially the way the letters shake and leave afterimages on being spelled out.
    Asriel: It's me...your best friend...
  • Suicide by Cop: Unintentional, but Asriel purposely held back his power and the Fallen Child's influence when the latter went to attack their hometown. The humans merely saw a monster carrying the Fallen's corpse and believed they were avenging them by slaying the monster — Asriel accepted this fate rather than let the Fallen annihilate them and possibly kickstart another war.
  • Super-Powered Evil Side: Asriel has no powers by himself, but he is nearly godlike when he is reincarnated as a murderous flower and also when he absorbs the souls of the Underground to become the Absolute GOD of Hyperdeath.
  • Tender Tears: Even admits that he's "a bit of a crybaby."
  • That Man Is Dead: Invokes it on himself to Frisk, claiming Flowey is so different that he's someone else.
  • Thou Shalt Not Kill: Played With. In the past, he refused to kill humans; in the present, while fighting him, he tries while attempting to do an infinite "game" with you, but your soul "refused" and will not die.
  • Time Crash: Seeks to cause one after another using the power of the Six Human SOULs along with every Monster SOUL — locking Frisk in an eternal loop of life with him so he'll never have to let them go.
  • Tragic Villain: He clung desperately to the memory of the Fallen Child, and was Forced into Evil as a result of his soulless reincarnation. He has suffered more than any other character, and despite all of Frisk's determination, you can't save him.
  • True Final Boss: Of the True Pacifist ending, which requires having gotten the Neutral-Pacifist ending. Interestingly, he's both a Climax Boss and a Zero-Effort Boss, since you can't lose.
  • Turn Out Like His Father: Inverted. In his powered-up form, he resembles his mother, more than his father.
  • Used to Be a Sweet Kid: Every indication from the story is that Asriel was just as kind as his parents, if not more so. Things quickly went downhill following his friendship with the Fallen Child, the subsequent Demonic Possession, and finally his reconstruction as Flowey without a soul. Getting killed because he refused to fight back and coming back unable to feel love twisted him into something totally unrecognizable from his former self.
  • Victory Is Boring: After his reincarnation and acquiring the power to "save", he actually did a lot of good deeds throughout the Underground, achieving the "best ending" possible. But lacking his love and emotions, found it was all hollow and pointless. He started going down evil paths to see if that would give him any satisfaction — only to brick-wall against fighting Sans.
  • Villain Respect: Being able to stay alive after being attacked by barrage after barrage of his god-like power makes him admit that Frisk really is "something special."
  • Wise Beyond Their Years: Asriel is pretty well-spoken in his child form, probably due to how many times he's reset the world as Flowey; despite not much time actually passing for the world, Asriel/Flowey himself has had a very long time to learn about things beyond his age.
  • Wishful Projection: Similarly during his time as Flowey, Asriel believes Frisk is the Fallen Child reborn, the difference is he finally loses the delusion upon his final defeat. Whether he's mistaken or not depends on if you did the Genocide route before the Pacifist route — if you did, the Fallen really is along for the ride, but Asriel doesn't really know this... which might be for the better, since that Fallen Child has long since stopped being the human Asriel knew.
  • Yandere: Just like his Flowey persona and for the same reasons, his desire to keep Frisk (who he thinks is Chara) in the Underground is a platonic variant. Unlike Flowey however, he grows out of it when he finally comes to his senses.
  • Zero-Effort Boss: The True Final Boss Asriel. While his attacks aren't easy to dodge, you automatically revive each time you die, and thus the battle keeps going until you win. While dying can prolong the battle, you ultimately can't lose. And his penultimate attack actively avoids harming you, being the exact same as Toriel's.

    The Fallen Child/"Playername"/Chara
It's me, (name).

"HP. ATK. DEF. GOLD. EXP. LV. Every time a number increases, that feeling. That's me."

Chara is a character of ambiguous age, gender, and personality, much like Frisk. When they were alive, it is said they ran away to Mt. Ebott because they hated humanity. Chara was the first human to ever fall into the Underground. They were adopted by Asgore and Toriel, becoming Asriel's best friend. But things took a dark turn when they tried to destroy the barrier by killing themselves, merging their soul with Asriel's, and using Asriel's body to go to the surface to gather six human souls.

Before they could hurt anyone, Asriel panicked and took back control. The humans saw a monster carrying Chara's body and mistook it for a murderer, killing Asriel (and Chara along with him). Chara's body was mummified and later buried beneath the flower patch in the Ruins, where Frisk would eventually land upon starting their journey; this stirs Chara's lingering spirit from their body and attaches it to Frisk, unwittingly bringing them along for the ride.

Chara's role is hotly debated among fans due to their seemingly-limited interaction with Frisk/the player. Early interpretations saw Chara as the game's over-arching villain, but fans have progressively found plenty of evidence in the game's lore and easter eggs that point to Chara being the game's narrator and quite possibly the player/Anomaly itself. Crossover between these interpretations is also very possible, as is the possibility of circumstances varying depending on what route is being taken. Worth noting that there is a wrench in this theory in the Japanese localization of the game - most of the game's dialogue is exclusively written in Kana, while Chara's dialogue is exclusively written in Kanji.

Despite the many theories about the Fallen, only one thing is for certain: if you pursue the Genocide Route, you're in for a bad time.

  • Abstract Apotheosis: As the character quote states, they are the embodiment of stats. On one hand, the fallen human probably becomes the embodiment of killing everything to gain power in the Genocide Route; in order to achieve 100% Completion, you have to do some pretty horrible things, including kill every single friend you've made in a previous run. On the other hand, the Fallen's stats help protect Frisk in the Pacifist route.
  • Ambiguous Gender: Just like Frisk, the Fallen Child's gender is left ambiguous. The canon name is "Chara" which is short for character and not indicative of anything. The ambiguity is understandable, since they're the one you're naming at the start of the game and they can be named after the player (or your cat).
  • Ambiguously Evil:
    • One of the most hotly debated examples in its time, the ambiguity of Chara's true nature and morality is an extraordinarily unclear and controversial topic. Very little can be said for certain about this character's true goals, especially in regards to the game's backstory. They may have been sincere with Asriel about wanting to kill only enough humans to break the barrier, or may have wanted to lay waste to their home village, or possibly to get revenge on the entire human race.
    • In addition, the game has many different story routes, and none of them are really "canon" or "non-canon"; what you personally played is what happened in your game. Therefore, it's easy to make a case in which the character is sympathetic if you only take into account the Pacifist run, but equally easy to argue for them being a villain if you only take into account a Genocide run, and the lines only get blurrier the more routes you take into account, in what order, and how many. Not too mention that it's difficult to say how much of the player's actions on any route Chara had a say in or not.
    • After completing a True Pacifist run, the player can walk all the way back to the first room of the game where they fell down, where they'll find Asriel. If talked to, he'll say that he became so fixated on Frisk because he saw them as Chara. However, he'll admit that this was an incorrect assumption, since, as a Pacifist, Frisk is "the kind of friend [he has] always wanted" whereas Chara "really wasn't the greatest person" and mentions Chara's vehement hatred of humanity.
    • At the same time, they were beloved by the entirety of the Underground, despite their bad history with humans, and they're implied to have had at least a few Pet the Dog moments in their past. As well, if the theory that they're the narrator is to be believe, they're helpful, love dogs, and generally fairly good-natured, if snarky, on the Neutral-and-better routes. It's also worth pointing out that Asriel admitting Chara wasn't the best person is similar to how Monster Kid can tell Frisk in the same True Pacifist epilogue (if Frisk saved Monster Kid before Undyne could) that Undyne "isn't actually as cool as we thought" and "just kinda... mean", which leaves room for interpretation of Chara, like Undyne, as a flawed, human-hating, but not irredeemable person.
  • Ambiguously Human: In addition to being able to exist in some form after death despite not being represented by a floating soul like the rest of the fallen humans, they exhibit powers by the end of the genocide run that pretty heavily suggest they've become... something new. Most notably, they're able to take the player's soul in exchange for getting the game back, despite the fact that the game clearly states that humans cannot take other human souls, possibly because Chara came back soulless as Flowey did.
  • And I Must Scream: In the Genocide route, and possibly in the other routes, Chara now remains stuck as a voice in Frisk's head. However, after completing the Genocide route, they can completely take Frisk's soul. Also, in the room with all of the sarcophagi, the red coffin yields the message, "It's as comfortable as it looks," which if the Narrator Chara theory holds water, suggests that after they died with Asriel and before Frisk landed on their grave, Chara might've somehow been conscious of being a corpse inside their coffin for all that time. And Asriel thought being turned into a daisy was bad.
  • The Antichrist: It is said that the Fallen's presence brought much hope to the Underground. If the fallen human is interpreted as Evil All Along, they are this. Otherwise, they may be an Anti-Hero.
  • Anti Anti Christ: One interpretation has the Fallen Human once being evil, but then turning good through the Pacifist route, supplying Frisk the final memory to save Asriel.
  • The Atoner: The Narrator Chara theory would make them this in the Pacifist Route. After being responsible for the death of their brother, the breakup of their parents, and Asgore declaring war on humanity, all by trying to kill people to save the Underground, now they're going to use Frisk to save everyone by not killing everyone. Averted in the Genocide route, although it could be said that the Soulless Pacifist ending represents them holding You/the Player/Anomaly responsible for your actions, thereby atoning for their part in the route.
  • Audience Surrogate: It's strongly implied that, on some level, they're supposed to be a representation of the player or some kind of vessel for the player's intentions. Exactly how far this goes is up for debate. Notably, you give them a name of your choice at the beginning of the game and you're encouraged via Word of God to give them your name (if you can't think of anything else — naming Chara after your cat is also permitted).
  • Ax-Crazy: Their narration leans this way in the Genocide route, to the point of counting down how many monsters are still alive in each area (ostensibly to help you know many are left to hunt down and kill) and their CHECK on Monster Kid saying "Looks like free EXP." Make it to Toriel's house and this pops up in red text:
    "Where are the knives."
    • This phrase can interpreted differently, as they could have been so horrified at this point that they wish to end this madness, since you can easily slay every single monster with murderous intentions alone.
  • Badass Bookworm: Assuming Chara is the narrator at all times, at one point (when helping the Royal Guards) the text "I see two lovers staring over the edge of the cauldron of hell" shows up, which is a reference to an obscure Japanese novel.
  • The Bad Guy Wins: If you go through with getting the Genocide ending, the first human wins. Forever. Even on subsequent playthroughs... well, that is, until a player erases all records of their corruption, but details, details...
  • Bad Samaritan: Want to back out of the Genocide run in the last minute? Or want to go Pacifist after you already helped them achieve their goals? The Fallen Child will turn on you.
  • Became Their Own Antithesis: Manages to be this in opposite directions, depending on how you interpret them. If you believe they were originally a Well-Intentioned Extremist who genuinely wanted to just free monsterkind, then the fact that their plan led to death, suffering, and widespread despair among the monsters makes them this trope — and in the Genocide route, it goes even farther by way of them destroying the entire world. If you believe that they originally were a bad person with dark ulterior motives (and buy into the Narrator Chara theory), then the Pacifist Route can be seen as their redemption.
  • Best Served Cold: According to some, The Fallen's hatred for humans unfortunately outweighed their love for their adopted family, and Asriel's betrayal and Chara's mummification was a catalyst for their murder spree.
  • Big Bad Duumvirate: Seemingly with Flowey on the Genocide Route, until it turns out Flowey is also on their hitlist as well...
  • Big Bad: For the Genocide route, and worst of all, it's your fault if they win. Though, they make it clear that it was your actions that caused the world's destruction.
  • Big Good: If interpreted as the narrator or player (see Anomaly), they are this for the Pacifist route.
  • Black Eyes of Evil: At the end of the Genocide route, Chara's eyes become noticeably wider, rounder black eyes. If you choose not to erase the world, their eyes will start dripping with something black before they rush the screen and crash the game.
  • Blank Slate: It's implied that after they died, they lost their SOUL and determination along with it. When the player names them, they are brought back and possibly grows a new personality depending on what route the player takes.
  • Blasphemous Boast: Inverted. The player would naturally assume that after doing a Genocide run, they can simply reset everything and play through again like nothing happened. Chara, having hijacked the game, rebukes them as a deity in the void of nothingness, telling them that their actions have real consequences, which they are now totally impotent to negate.
  • Blush Sticker: Has a permanent rosy blush to their cheeks.
  • Body Surf: The fallen human and Asriel planned to unseal the barrier by having Asriel take their soul, going up, and taking six more souls. Asriel backed out halfway through, killing them both. In the Genocide Route (or all routes, according to some fan theories), the Fallen Human now resides in Frisk.
  • Bootstrapped Leitmotif:
    • Small Shock, Memory, or His Theme can double as Chara's theme, but for the Genocide route, slow Anticipation down and you get the first human's oppressively mechanical theme, In My Way, which is also used at the end of the demo if you go for a Genocide, right as Chara comments "That was fun. Let's finish the job."
    • There's also that creepy minimalistic theme that plays when you meet them in person at the end of this route.
    • Some people also believe that Once Upon a Time (one half of the game's Theme Tune) is their theme; this is mostly because, though it shows up in many places throughout the game (outside of during a Genocide run), it is most prevalent when Chara is involved in some way.
    • Some fans also believe Megalovania could be their Leitmotif or Battle Theme Music for the Genocide Route, since the title is very similar to the term "megalomania", which is an unnatural desire for power, which is exactly what Chara says they're after upon completion of the Genocide route. Some have also theorized that Megalovania could be the Anomaly's theme instead, though.
    • Then there's Megalo Strike Back, a song Toby Fox made that isn't even in the game. This is mainly because the song was originally associated with Giygas, another character associated with death-bringing power and hatred of humanity.
    • Thanks to the team behind "Undertale the Musical", and "Undertale the Narrator's Musical" following afterward, Star, an unused track, has become this for Chara as well. It also helps that there actually is a star by that name, said to be one of the stars most likely to support life.
  • Broken Bird: Sympathetic portrayals tend to be this. Even if they aren't or never were evil, it's obvious that the Fallen Human was/is seriously messed up.
  • Broken Pedestal: For Asriel in the True Pacifist route. He was deeply devoted and loyal to them when the two were alive, and as Flowey they're the only person he's even tries to care about anymore, with him believing they were right and he was wrong in trying to kill people and taking after them in making "creepy faces". It hits the point that he deludes himself into believing Frisk is Chara because he's that desperate to have them back. After Frisk manages to withstand all Asriel's attacks and eventually save him though, Asriel realizes he was right to not let Chara kill anyone, compares the relentlessly kind and pacifistic Frisk to Chara who'd been so consumed by their hatred of humanity, and finally and reluctantly admits Chara wasn't the best person, unlike Frisk who is the kind of friend he wishes he always had. With that said, if you try to play again, it's Chara he addresses as the one he believes is in charge of the resets, and he still seems to trust that they are well-meaning and can be reasoned with (going out of his way to reassure them that this is the happiest outcome for everyone, and believing they were fighting to stop the resets), appearing somewhat awkward and melancholy but not bitter with them. So no longer the greatest person in his eyes, but perhaps not a bad one either.
  • Broken Smile:
    • A different interpretation of Chara laughing at getting Asgore sick is that it was a way to cope with their mistake and they didn't find any amusement from it at all. Asriel even says that he wishes he'd laughed it off like Chara did, which could support this take on it.
    • Pops up again (with the same ambiguity) in one of the sadder/more horrifying moments of the Pacifist Route: "You laugh, and keep laughing. It's SO funny, you can't stop. Tears run down your face...". Though they acknowledge that "But it’s not funny", implying that the first laugh was a coping mechanism.
  • But Thou Must!: Choosing to not erase the world has the fallen human tell you that you're not in control, then does it anyway. Selecting the option on any subsequent Genocide playthrough has Chara say that "you made your choice long ago," and still do it.
  • Cain and Abel: The interpretation that Chara was a bad seed from the start positions them and Asriel this way, with Chara as the manipulative, ill-intentioned sibling using their innocent and adoring best friend and brother Asriel for their own purposes, up to deliberately poisoning their father for a laugh and trying to use Asriel to kill humans. Come the Genocide route, Asriel has undergone a Face–Heel Turn and together they are Siblings in Crime, though the last part of the route is to have Chara kill Asriel as well and come full-circle with the Cain and Abel trope.
  • Came Back Strong: If they are the narrator of the Pacifist route, then they are kinder and wiser than they were implied to be in life, and help Frisk SAVE Asriel and break the barrier.
  • Came Back Wrong: In the Genocide route, Sans and even Asgore, their own adoptive father, fail to even recognize them as human by the time it's all over. And let's not even start on when they finally show themselves to thank you for "guiding them."
  • Canon Name: The Fallen Child's name is whatever you chose at the start of the game, though the names of some characters will be denied. Promotional material for the game had the player's name set as "CHARA" (as in character), which is said to be the "true name" if you input it. "Mainchara/Truechara" is what Frisk's and the Fallen Child's sprites are named within the game and the game defaults to "CHARA" as their name if the player manages to skip the naming screen.
  • Care-Bear Stare: For the Pacifist route, if they are believed to be the narrator or player. They may have hated humanity, but even though it would only take the monsters getting Frisk's soul for Asgore to unseal the barrier and declare war, they aid Frisk in saving everyone, monsters and humans, without a single person getting hurt.
  • Color Contrast: Wears yellow, green, and brown in contrast to Frisk's blue and purple, notable as they are the only two humans seen in the game. Averted with their souls, which are both red.
  • The Corruptible: If one subscribes to the "Narrator Chara" theory, then it seems like that they were turned into an Omnicidal Maniac by the Anomaly's influence.
  • Create Your Own Villain: If you subscribe to the "Chara represents your actions" theory, you're the one that pushes Chara over the edge.
  • Creepy Child: Even in life, the Fallen Child was described as being able to do a "creepy face" (it amused Asriel though), laughing off Asgore getting sick (though whether it was nervous guilty laughter or malevolent laughter could be unclear), nursing a hatred for humanity, and being willing to kill themself and other humans.
  • Creepy Monotone: The further you go down the Genocide route, the more monotone the narration becomes. By the final cutscene, the Fallen Child speaks in a deadpan tone, without Voice Grunting and in mostly short sentences.
  • Cruel and Unusual Death: Killed themselves intentionally by eating relatively-fresh buttercups. It's probably better you don't know what eating buttercups can do to your digestive system and bowels.
  • Cry Laughing: If one subscribes to the "Narrator Chara" theory, then there's a moment in the "So Cold" amalgam fight where, upon selecting the "Laugh" ACT option, it says "You laugh, and keep laughing. It's so funny you can't stop. Tears run down your face. (Beat) What? You didn't do that?" This could be interpreted as Chara being the one crying, and not Frisk.
  • Cute and Psycho:
    • The cute part is played straight all the time, while the psycho part only applies to Chara if the latter goes for a Genocide.
    • Chara could also be considered this to a lesser extent when they was alive, depending on what you consider their view of humanity, monsters, and the Dreemurrs was.
  • The Dark Side: Becomes increasingly corrupt with the more EXP and LV you gain.
  • Dark and Troubled Past: Asriel implies that Chara had sad reasons to run away from home.
  • Deadpan Snarker: If you believe the Narrator Chara theory. No matter the route, the game's narration is full of sarcasm and dry observations. Even in the Genocide route, Chara says Monster Kid looks like "free EXP."
    *after failing a puzzle* Wow. You are super fast at being wrong!
    *examining behind Papyrus' sentry station* ?!... There's a camera behind the... "sentry station."
  • Deal with the Devil: If you choose to Earn Your Bad Ending and try to start up the game again, you'll see that the world has been destroyed by Chara. However, Chara will make you an offer to restore the world if you give up Frisk's SOUL, which will theoretically give you an opportunity to amend for things... Except that's not how it works out. Enjoy the Sudden Downer Ending you get if you try to go Pacifist!
  • Death Seeker: Implied in the backstory. They climbed Mt. Ebott, where people are said never to return from, for reasons that weren't "very happy," according to Asriel.
  • Decoy Protagonist: After a fashion in the Pacifist and Neutral runs. The opening of the game, along with the subsequent naming sequence, lead the player to believe that Chara is the character they're playing as. It's not until the end of the Pacifist run that it's made clear that the player character is Frisk.
  • Demonic Possession: In the Genocide route, the Fallen gradually begins to act independently of the player's inputs, which culminates in them killing Asgore and Flowey without any input from the playernote . (And ignoring your choice to not destroy the world in the Genocide ending.) If you sell Frisk's SOUL in the ending and reset for True Pacifist, the Fallen escapes the Underground under the guise of Frisk. If you try to tear yourself away, they'll remind you that you were never in control.
  • Determinator: It's worth noting that one of the few concrete things we do know about them is that they put themself through an agonizing death to pursue their and Asriel's goals. Because they had the same color soul as Frisk and many fans theorize that determination is red souls' key trait, those fans also assume Chara was a Determinator like Frisk. Whether they were ever able to harness their determination to control time the way Frisk can (and, it's suggested, the other six fallen humans could) is never touched on.
  • Diabolus ex Nihilo: Along with Frisk, little is known about Chara's reason to visit Mt. Ebott, their life before the underground, or why they have a hatred for humanity.
  • Didn't See That Coming: Chara assumed correctly that Asriel would absorb their soul after they died. They didn't realize that Asriel could or would still stop them from killing humans, though. With Asriel holding Chara back, they end up sustaining mortal injuries from the human mob and their plan fell apart.
  • Dissonant Serenity: Once the Fallen Child introduces themselves, they look a lot like Frisk but with their eyes wide open, a Blush Sticker, and a hearty smile instead. If you refuse to erase the world though, they don't even seem upset, but they will mock you for thinking you were in control and crash the game with a Jump Scare, complete with a creepy face and Evil Laugh.
  • The Dog Bites Back: One interpretation of the Fallen Child turning against you in the Genocide ending and hijacking your Pacifist endings. After all, you made them destroy everything and everyone they cared about, showing that you didn't really care about the monsters, then tried to get away with it by making everyone forget and going for a happy ending anyway.
  • The Dreaded: There are no townspeople in the Genocide Route; the NPCs have all evacuated and hid in a shelter somewhere, not stopping to clean out their money drawers. Doggo shivers when Frisk approaches him, perhaps because the game does its best to guilt trip the player for what they are doing.
  • Driven to Suicide: Highly implied to be the reason they climbed the mountain in the first place. According to Asriel, "he knew the reason Chara climbed the mountain. It wasn't for a very happy reason." A conversation with Flowey in the Genocide Route toys with the idea Chara erasing themselves was the reason.
    Flowey: But I decided it wasn't worth living anymore. I decided to follow your footsteps. I would erase myself from existence.
  • Drone of Dread: After the protagonist empties the ruins of enemies, the music for the area changes to a distorted ambient track. This track is called "But Nobody Came"note . After exiting the Ruins, all overworld songs are lower pitch, slower versions of their usual counterparts.
  • Eldritch Abomination: They become a world destroying one by the end of a Genocide Route.
  • Emotion Eater: One interpretation is if Asriel became soulless when he attaches to a flower, Chara might have done the same with Frisk. According to Asriel, he can only feel the feelings of the soul he's attached to, so it would also explain why Chara's emotions reflect Frisk's actions: Chara's narration grows warmer over the course of the Pacifist Route, while it grows colder over the Genocide route.
  • The Empath: If we assume they're the narrator, they seem surprisingly good at reading Frisk's emotions at certain moments, which is awfully impressive considering how nonplussed Frisk looks most of the time. Symbiotic Possession might or might not factor into it. Asriel also states several times that Chara was the only one who could understand him in lifetime and even when they returned to life as Chara is a souless creature like him...
  • Even Evil Has Loved Ones: While they were still human, they seemed to have some measure of love for Asriel and his family (notice how the family's photo is angled towards their bed). There's even evidence that this affection carries over into the Genocide route, although it doesn't stop them from killing Asgore (without player input) or hacking Asriel to bits (once you nudge them into it).
  • Even Evil Has Standards:
    • It's subtly implied throughout the game that the Fallen Child is the narrator for all the Flavor Text. This flavor text includes calling you out for taking more than one Monster Candy or for deliberately wasting an entire cooler full of water in front of an overheated Undyne. Assuming that Chara is villainous and that these lines aren't meant to be sarcastic, then apparently, killing everyone and destroying the world is fine, but that stuff is beyond the pale.
    • If you complete the Genocide run and come back to the game wanting another playthrough, they'll call you out on thinking you're above consequences. After all, you just killed their entire family and their only home after they sacrificed themselves (in vain) to save everyone.
    • Playing through another Genocide run has the Fallen Child accuse you of having a "perverted sentimentality" that they cannot fully comprehend. They even feel the need to suggest going for another ending. Unfortunately, if you've complete the pacifist route, they will kill all of your friends and will never let you have your happy ending, probably as revenge against you.
  • Evil Counterpart: One interpretation sees Chara as the Anti-Christ to Frisk's Christ. The two kids even look similar, except for the color of their clothes and skin, and Fallen's disturbingly sunny disposition. Chara's jumper (yellow and green) is a color negative of Frisk's (blue and purple), for instance.
  • Evil Has a Bad Sense of Humor:
    • "That comedian..." The "comedian" in question is Snowdrake. If Snowdrake is not dead before the counter is exhausted, the SAVE point text will change to "The comedian got away. Failure", and the Genocide route will be aborted. Boy, tough crowd.
    • What few jokes Chara does make in this route lean toward the tasteless side. Upon being inspected, the hole in the laboratory wall will yield the message "It's just here to complete the look."
    • They will describe the bag of dog food as "half-empty" (as opposed to "half-full" if no one is killed), followed by the message "You just remembered something funny." This message appears after killing Lesser Dog, Greater Dog, and Doggo and more than 20 monsters, likely implying their potential of getting corrupted.
  • Evil Is Not a Toy: With you on the receiving end. In the Genocide Route, you take control of them, and Frisk, and gleefully slaughter your way through the Underground, corrupting them further with every drop of LOVE and EXP...but at the end, you've made them strong enough to wrest control from you and destroy the game of their own accord, forcing you to sell Frisk's SOUL to them. Say goodbye to your happy ending... forever.
  • Evil Laugh: From the Tainted Pacifist Ending. If you choose to stay with Toriel. It's even more horrible than Photoshop Flowey's! You can also hear the traces of one in their jumpscare if you choose not to destroy the world in the Genocide route's conclusion.
  • Evil Only Has to Win Once: No matter how many times you finish the game with a Pacifist ending, all it takes is for you to reset the game and finish it with one Genocide, and all of your runs from then on will be doomed to end with a horrible ending, no matter what you do. The only way to reverse that is by going outside the game to edit save files or alter how the game reads them.
  • Evil Weapon: We don't see what the Real Knife looks like in-game, but judging by its Steam Trading card, it glows blood-red. True enough, hacking the game as to get the Real Knife early (or on a non-Genocide run) would make most monsters instantly Spareable, implying even the monsters can see how evil this weapon is. However, a possible plot twist is that it's just the worn dagger but from another perspective.
  • Eviler Than Thou: By the end of a Genocide playthrough, even Flowey is terrified of them, and is eventually reduced to begging to be spared. Should you feel remorse and refuse to destroy the world, they'll point out you don't have any say in the matter and prevent you from playing the game.
  • Exact Words: The name entry screen asks you to "name the fallen human." It never said which fallen human. The child being "fallen" can also refer both to the child having fallen into the Underground, fallen as in "died," or "fallen from grace."
  • Exposition Fairy: Acts as this for most (if not all) of the Genocide run. The Narrator Chara theory posits that they are this in Neutral and Pacifist runs as well.
  • Eye Awaken: If you happen to clear a Pacifist run and stay with Toriel after selling Frisk's soul to the Fallen, the last cutscene of Toriel bringing pie to Frisk ends with them waking up after she leaves, with red eyes, a huge grin, and a terrifying laugh.
  • Face of an Angel, Mind of a Demon: At the end of a Genocide run, their rosy dimples and sunny smile run entirely counter to the kind of creature they actually are at that point.
  • The Faceless: Has their face hidden in the intro and in Asriel's flashbacks. It's only in the Genocide route when we see their face.
  • Faux Affably Evil: They're quite genial and even grateful towards a Genocide player for awakening them from death. But if the player chooses to disobey them at the very end, their ugly side comes out immediately.
    • One interpretation of the narrator theory is that they're merely putting up the facade of an aloof narrator in the Pacifist run, biding their time until you decide to give them the EXP they need to get stronger.
  • Foreshadowing: Depending on the route, regarding their true nature.
    • For the Genocide Route, when you finally get to Toriel's house and inspect the kitchen...
    • During the Genocide route cutscenes, Frisk will sometimes walk forward, despite your controls not working. It is believed the Fallen Child is taking direct control.
    • For the Pacifist route, in the True Lab, none of the enemies seem to have a list of ACTs, and even when you use those actions, Frisk doesn't quite respond to them normally. And then you play the video tapes discussing the fallen human...
  • The Fourth Wall Will Not Protect You: Want to go back and reset after the Genocide Route? Bad news: Chara destroys the game. Literally. The final thing Chara attacks is the game itself.
  • Greater-Scope Villain: The First Child is this during the Neutral run due to being responsible for all of the recent problems in the Underground.
  • The Grinch: In the Genocide route, inspecting the Christmas tree at the center of town displays the message "Nothing for you." The protagonist can also take three snowman pieces from the Snowman until he becomes a "useless pile of snow".
  • Heartbeat Soundtrack: Their theme when they speak with you in the Genocide run involves a hollow, creepy use of this.
  • Heel–Face Turn: One way to interpret their character arc, if one believes they were villainous in life but redeem themselves in the Pacifist Route.
  • Hello, [Insert Name Here]: When asked to enter a name at the beginning of the game, they are the person you are naming, rather than the character you are controlling.
  • Hidden Depths: Gerson indirectly implied that while living with the Dreemurr family, they were just as embarrassed as Asriel by Toriel and Asgore's moments of being Sickeningly Sweethearts.
    • If you subscribe to the Narrator Chara theory, suddenly they gain a lot more character.note  Aside from sounding fond of Frisk despite their stated hatred of humanity, they are usually composed but have a witty, sometimes sarcastic and sometimes juvenile sense of humor, try to nudge you into showing mercy to monsters, seem disappointed in you if you're a jerk, and keep their relationship to the Dreemurrs hidden from Frisk outside of the Genocide route. They seem to like animals, gushing over dogs throughout the battles to even Toby Fox's own Tweet about what would happen if Chara encountered a Cat Mettaton (Mettaton MEOW). (Archived post.) There are also some indications throughout the game that they may have had a passion for botany, having a special fondness for the golden flowers from their village, an enthusiasm with learning about the "typha" in Toriel's gardening books, and Asgore having planned on giving them a "Worn Dagger," which the narration identifies as a perfect gardening tool. Given that they know what a Tsundere is, they also seem to have pretty well-versed in pop culture or at the very least been aware of common tropes. The Genocide route also has them quoting Kitchen, a Japanese novel aimed at adults and not kids, so they seem to have been a very advanced reader for their age (whatever it was).
  • Hidden Villain: Despite being the catalyst of the Dreemurr family's breakup, Asgore's declaration of war against humanity, and Asriel's death then revival as the wicked Flowey, none of the characters save for Frisk, Flowey/Asriel, and possibly Sans ever uncover or know of the First Child's impact on these events by any ending, including the Golden Ending. Although, the Easter Egg on the naming screen where you can attempt to name the First Child after the main characters may prove otherwise if such is canon.
  • Hijacking Cthulhu: If Chara is in fact the narrator, then this actually happens to them in the Pacifist route: Frisk's emotions rub off on Chara in the same way the monsters help Asriel feel again, and Chara becomes a benign force influenced by Frisk.
  • Humanoid Abomination: They were (most likely) a normal human child in life, after dying and reviving, they have become a very different ghost. At the end of the Genocide Route they gain access to several Lovecraftian Superpowers that are fairly unique to them and very terrifying, such as a Game Face that involves their eyes and face melting away, Grand Theft Me / Demonic Possession abilities, the ability to override the player, Break The Fourth Wall, completely erase and recreate reality and take the player's (or Frisk's) SOUL (a particularly disturbing feat since it's established that Humans cannot take Human souls but Chara can take your SOUL just fine).
  • I Have Many Names: According to them in the Genocide Route, whatever name you choose for the fallen one at the beginning awakens them.
  • I Know Your True Name: When attempting to name the fallen child "Chara," the response becomes "The true name."
  • Ill Child: You learn on the Neutral path that they suddenly became very ill and died, with no explanation given; this leads to Asriel's death, Asgore's vow of revenge, and Toriel's departure. On the True Pacifist path, you find out that they deliberately poisoned themself as a Thanatos Gambit.
  • Interactive Narrator: If they really are the narrator, they're this trope to previously unheard of extents, starting with them being able to tell Frisk/the Player about different monsters by Checking them and the Player being able to affect and corrupt Chara by killing monsters, making the narrative itself change and reflect your choices and actions, and finally ending with them subjecting you to the horrifying narrative tone you gave the story in the Genocide run.
  • Interspecies Adoption: Adopted by the Dreemurr family, a family of monsters, after falling into the Underground, making them adopted royalty to boot.
  • Jerk with a Heart of Gold: If they did genuinely care about Asriel and/or wanted to free the monsters. They hatched up a plan that would involve killing people to free their adoptive family. If they're interpreted as the narrator, they're also this way to Frisk in their sarcastic comments. However...
  • Jerk with a Heart of Jerk: If they never cared about the Dreemurr family or the monster race, then they're this.
  • Knife Nut: Knives are their Weapon of Choice in fan works, and they are associated with the Worn Dagger/Real Knife found in the bedroom they shared with Asriel. Then in the Genocide route, there's their infamous "Where are the knives" line in Toriel's house (in eye-popping red text), and their flavor text about the Real Knife is the only time the Genocide narration breaks from its usual cold and terse tone, sounding downright gleeful about getting their hands on it.
  • Lack of Empathy: It's implied that, like Flowey, the fallen human has no soul and literally cannot feel empathy or love. If you complete a second Genocide run, Chara will note a "strange feeling" in the soul they've claimed from you, what they call a "perverted sentimentality", and will admit they can't understand the feelings you have towards the world of Undertale anymore, though it's not clear if this is because they might not have a soul of their own anymore, because they've become too warped by LV, or they're just outright admitting even they don't know what's wrong with you to keep doing this.
  • Lemony Narrator: If one believes that they narrate the Pacifist and Neutral routes. They regularly tease and joke with Frisk, make sarcastic comments about the scenery, and rename the items into funny abbreviations during battles (e.g. Butterscotch-Cinnamon Pie becomes "ButtsPie") and give advice on how to spare monsters.
  • Lethal Chef: Putting buttercups instead of cups of butter into a butterscotch pie made for Asgore.
  • Look Behind You: If you die to Undyne the Undying and try again, Chara uses this on the Monster Kid to get him to drop his guard quicker.
  • Mask of Sanity: While initially cast in a sympathetic light, Asriel admits at the end of True Pacifist mode that Chara "...wasn't really the greatest person" and adds that they "hated humanity," indicating some misanthropy. Asriel also mentions that Chara laughed it off when the two of them accidentally poisoned Asgore. However, some fans think this was done on purpose, and that Chara wasn't merely laughing off the situation, but just laughing.
  • Meaningful Name: It's worth noting that "Chara", along with being based on the word "Character", is a name ("Cara" or "Kara") which means "loved one" or "beloved", which fits as Chara was beloved by the Underground when alive. Now it might seem to be an Ironic Name for them during the Genocide route, but when you take into account what LOVE stands for in Undertale...
    • "Chara" is also the name of a species of aquatic plant; Chara's narration implies that they were fond of gardening (to the point of calling the Worn Dagger a "gardening tool").
    • "Chara" is also the name of a star in a binary star system, which may be a connection to the unused track "Star" on the Undertale Soundtrack. A dual star system would be an appropriate description for them and either Frisk or Asriel.
    • It's also Irish for "friend", fitting a character repeatedly referred to as Asriel's best friend.
    • "Kara" in Polish translates literally to "punishment." Given the endings of Soulless Pacifist runs...
  • Memento Macguffin: The Locket, which is found alongside the Real Knife towards the end of the No Mercy Run. Chara mentions that Frisk can "feel it beating", and when they put it on:
    "Right where it belongs."
  • Metaphorically True: You are asked to name the "Fallen Child" at the beginning of the story, giving you the impression the game meant Frisk, when it really meant the Fallen Child.
  • The Mirror Shows Your True Self:
    • Interacting with anything that shows Frisk's reflection/image (a mirror or a monitor) while on a No Mercy run will give "It's me, Chara" as the description. Which is possibly projection, since many notes that Frisk/the player acts like a souless person in the genocide run.
    • In debug mode, it is possible to have unused "Chara" sprites appear as the protagonist's reflection in puddles and mirrors; this was probably going to be a feature in post-Genocide playthroughs.
  • Misanthrope Supreme: They developed a hatred of their home village and humanity before arriving in the Underground, and tried to make good on their plan to unleash their and Asriel's combined "full power" and kill at least six humans. How many targets they really had, and whether it was for the monsters' sake or for their own vengeance, is up to the player's interpretation.
  • Mission Control: In the Genocide route, they advise Frisk that Sans can't keep dodging and to just keep attacking.
  • Mission Control Is Off Its Meds: Played straight in the Genocide route, even telling the player that Monster Kid is just free EXP.
  • Morality Pet:
    • The Fallen Child for Flowey/Asriel, shown most prominently in a Genocide Run where he solves puzzles for you and otherwise helps you along because he thinks that the Human Child is possessed by the Fallen Child. As demonstrated by how satisfied the Fallen sounds to have the Locket — a Friendship Trinket celebrating their bond with Asriel — "right where it belongs" if you equip it, and the Fallen's hesitating and needing the final push from you to kill him at the end of the Genocide Route, the feeling is somewhat mutual even then.
    • If the narrator theory is to be believed, Frisk might be one for them in the Pacifist Route, which would be especially impressive considering one of the Fallen Child's few established traits is their hatred of humans.
  • Murder in the Family: They are definitively confirmed to be present by the end of the Genocide route, which requires the deaths of both their adopted parents and their adopted brother. The degree of control they may have over Frisk's body isn't clear, but it is widely held that they are the force responsible for the killing blows on at least their dad Asgore and on Flowey (who is their brother Asriel); while the player does have push a button to initiate the kill on Flowey, attacking and killing Asgore happens automatically and the player also doesn't do anything to control the many, many attacks unleashed on Flowey after that first click. Immediately after, Chara reveals themself to thank the player for teaching them to kill for power, and erases the world.
  • My Death Is Just the Beginning: The First Child convinced Asriel to go along with a plan to poison them, so that Asriel could absorb their soul, and the two could pass through the barrier, allowing them to take the souls of six additional humans to open the barrier. This plan fails when Asriel gets cold feet and resists the First Child's attempt to attack the humans at the village they arrive in.
  • My Rules Are Not Your Rules: Manages to pull this on both Sans and the player during the last Genocide boss fight. Throughout the fight, both you and Sans understandably expect the FIGHT command to initiate one attack per turn. But after Sans dodges your attack yet again after using his "special attack", Chara retaliates on their own with a second unprompted attack.
  • Mysterious Past: Although it's been said that Chara's reason for traveling to Mt Ebott was because they hated humanity. Though exactly what made them hate other humans is unknown.
  • Narrator All Along: A widely-held theory within the Undertale community, though not necessarily the case.
  • Nice Job Breaking It, Hero!: For you/Frisk. In their first and only appearance in the game itself, at the end of a Genocide run Chara reveals that the protagonist's "human soul" and "determination" were the cause of their reincarnation and that the protagonist's murderous ways has led Chara to believe that the purpose of their awakening was power itself. If you want to play the game again and try another route, you have to sell Chara your/Frisk's soul first, and if you ever get the Golden Ending, it's implied Chara takes over Frisk's body to do their own Genocide run offscreen.
  • Nightmare Face: In the No Mercy route, if you refuse to erase the whole universe, their eyes and mouth warp and melt unnaturally as they laugh maniacally and rush the screen in a Jump Scare.
    • Apparently, they also pulled a creepy face to tease Asriel, according to the tapes in the True Lab. Asriel gets them to scare him with it, but we only have his reaction to go on and never see it due to Asriel forgetting to take the lens cap off the video camera. This is likely where Asriel got the idea to make horrifying faces as Flowey.
  • No Kill Like Overkill: Near the end of the Genocide Route, if you choose to attack Flowey, Chara/Frisk doesn't just strike him, but hacks away at him over and over until there's nothing left. And then, for the final kill of the Genocide route, The Fallen attacks the game itself, which fills the entire screen with 9's, causing it (and the window itself if the game's being played in windowed mode) to shake uncontrollably and close the game. Rebooting it will open up to nothing but an empty void and the sound of howling wind.
  • Not Too Dead to Save the Day: In the Final Boss fight of the True Pacifist route, Chara's memory of meeting Asriel is what enables Frisk to save him and get the happiest ending despite Chara being long dead. If the Narrator Chara theory is true, they likely lent a helping hand willingly.
  • Omnicidal Maniac: At the end of the Genocide route, they erase the whole world whether you agree to it or not, destroying all life left after your killing spree in the Underground. And before they do it, they'll mention wanting to "move on" to the next world with you, implicitly so the two of you can do the same thing all over again to other worlds. Though even they won't understand your obsession with destroying everything if you choose to have them recreate the world just to destroy it all again.
  • O.O.C. Is Serious Business:
  • Our Ghosts Are Different: VERY DIFFERENT.
  • Pay Evil unto Evil: One interpretation from the endings of the SOUL less True Pacifist Route is, that Chara reminds the Anomaly, that they are "not above consequences". It still remains questionable, if they did indeed kill everyone simply because they want to, to apply the lessons the player have taught them or because they consider that you don't deserve your happy ending.
  • Player Character: Either a subversion or double subversion, depending on how you view Chara: are they the main villain, the narrator, or are you controlling Frisk because you are Chara?
  • Poisonous Friend: The Fallen pressured Asriel into a plan that would ultimately involve murdering humans no matter what. It backfired, killing them both. If after completing a True Pacifist run, the player walks all the way back to the first screen to talk to him, Asriel will expressly state this, admitting that Chara probably wasn't the greatest person and he shouldn't have so idolizing of them.
  • "Psycho" Strings: An unearthly, screechy-sounding noise forms part of their Genocide Route leitmotif, from when you encounter them at the end of a No Mercy route.
  • Rainbow Speak: By the end of the Genocide Route, much of their narration turns blood red. They also do this several times in the main game, presuming that they remain the narrator across all routes. It seems to be used to indicate strong emotion... or sarcasm, as indicated by the below quote.
    "Ah! Woah! Wow! It's a hole."
  • Reaching Between the Lines: The 9999999999999999 was the WORLD being hit, hence the screen shuddering on 'impact.'
  • Reality Warper: The Fallen Human, Chara, has the ability to completely erase or to recreate reality.
  • "The Reason You Suck" Speech: Delivers a few pretty scathing ones towards you after doing a Genocide route—
    The Fallen Child (continuing after the first playthrough): It was you who pushed everything to its edge. It was you who led the world to its destruction. But you cannot accept it. You think you are above consequences.
    The Fallen Child (after reaching the end of the second Genocide playthrough): But, you and I are not the same, are we? This SOUL resonates with a strange feeling. There is a reason you continue to recreate this world. There is a reason you continue to destroy it. You. You are wracked with a perverted sentimentality.
  • Redemption Quest: One interpretation of the player character is that they're the reincarnation of Chara, given a small shred of empathy by being bonded with Asriel. If this is true, the entirety of the Pacifist Run may be seen as this for the Fallen Child.
    • Alternately, you might be guiding Frisk through a Redemption Quest on behalf of humanity as a whole. One theory about Chara is that they're spiritually tailing Frisk to see if humanity is still as screwed-up as they remember.
  • Red Eyes, Take Warning: In the Soulless Pacifist version of the scene where Frisk is shown living with Toriel, the Fallen's eyes glow red as they remind you they now own Frisk's soul. Fandom regularly depicts Chara with red eyes at all times, whether they're evil or not.
  • Revenge by Proxy: Their implied motive for killing monsters in the post-Genocide Pacifist ending is to get revenge on the player.
  • Rewarded as a Traitor Deserves: After Flowey kills his father (having tried and failed to warn him of Chara), he tries to make himself seem useful so Chara won't kill him. He gets hacked to pieces for his trouble.
  • Riddle for the Ages:
    • What was the Fallen Child like before the events of the game? Did they Used to Be a Sweet Kid that got pushed over the edge? Or were they always an Enfant Terrible that only saw their adoptive family as stepping stones for their revenge? There's no definitive answer, and the few hints we're given could point to either extreme or anything in between, and as a result their ultimate reasons and motivations for doing what they do are also shrouded in mystery. Some mysteries that are hotly debated included...
      • Did Chara poison Asgore by accident, or was it on purpose? On one hand, cups of butter and buttercups are a spoonerism, but those who believe Chara was truly evil think Chara did it on purpose. In addition to this, when Asriel says Chara laughed off the situation, was it a nervous laugh because it was a bad pun? A nervous laugh out of fear? Or an Evil Laugh because they were completely evil?
      • Did Chara truly care for Asriel and the Dreemurr family, or see Asriel as a stepping stone for getting revenge on humanity? There are plenty of small details that point to Chara being the joy of the Underground when they were alive, but other see this as a mask to darker intentions.
      • What was their relationship with Asriel like? Interpretations swing wildly between Chara and Asriel truly being best friends that went awry, to Chara being Asriel's abuser and manipulator.
      • Did the fallen human actually want to unseal the barrier? Or was it a means to destroy humanity? Or did they intend to unseal the barrier and destroy humanity in order to let monsters inherit the surface?
    • Another major question is the extent to which the player influences them as a character. The EXP and LV values the player is shown on the interface are for Chara, not Frisk, and it's through the player's choices that their LV and EXP rise. This, along with dialogue thanking the player for their guidance in the Genocide ending suggest that the player's actions twist the first child into an Omnicidal Maniac, rather than them having been that way all along.
    • Is the Fallen Child making Frisk move during cutscenes in the Genocide route, or is Frisk moving on their own? The former is widely accepted among the community, although Asriel's dialogue in the epilogue hints that he could take away control at any time, just as Frisk may be taking away control from you, the player.
  • Roaring Rampage of Revenge: A possible interpretation of Chara's aggression towards Flowey at the end of the Genocide route as the flower is Asriel, after all, who got them both killed, and a potential interpretation of Chara's actions leading to them killing themselves so Asriel could take their soul, seeing as they hated humanity.
  • Sanity Slippage: Some theories suggest that the progressive effects of EXP and LV corrupt Chara from a benign force, to a being Driven to Suicide and at the end of the spectrum into an Omnicidal Maniac.
  • The Scapegoat: Regardless of how one interprets Chara, both as a person and how they fit into the story's meta narrative, at the end of the day, it's still the player's responsibility to choose violence or mercy. Even if they're interpreted as an abstract representation of you or your own temptation or something similar, nothing ever forces you to kill note , and yet many players erroneously attribute their own actions to them. The game itself seems to have predicted this, as Chara has this to say if you commit genocide and then try to undo it:
    Chara: Interesting. You want to go back. You want to go back to the world you destroyed. It was you who pushed everything to its edge. It was you who led the world to its destruction. But you cannot accept it. You think you are above consequences.
  • Screw This, I'm Out of Here!: Chara's narration is completely absent during the Omega Flowey fight, aside from "You called for help", and exclaiming that Flowey's defense has dropped to zero when the souls finally help you out. This is justified though in that, while Chara likely lived long enough in the Underground to know the strengths and weaknesses of each monster, Omega Flowey is a complete Eldritch Abomination that Chara's never seen before. The narration is also oddly absent during the Toriel and Asgore bosses, frequently becoming simply Visible Silence.
  • Sealed Evil in a Can: Some fans believe that after they're "awakened" at the beginning of the game, they're powerless to actually do anything unless you "feed" them enough EXP to fully come back from the dead. Some fans believe this corrupts them, turning them from good to evil, while others believe they're either biding their time or too weak to fully express their true personality during non-Genocide routes, making them a very abstract example of this trope.
  • Secret Test of Character: One of the theories about Chara is that they're keeping an eye on Frisk to see if humanity is still as messed-up as they remember.
  • Senseless Sacrifice: They killed themselves (by poisoning themselves with buttercups, while we're at it) so they could merge their soul with Asriel's, cross the barrier, gather six more human souls by killing six more humans, and returning to destroy the barrier for good. At the last second, Asriel became terrified of the Fallen's plan and took away control from them before they carry out the plan. As a result, the humans killed Asriel (and Chara along with him), led to despair among the Underground, Asgore declaring war on humanity, Toriel leaving Asgore, and Asriel ending up as Flowey.
  • Sesquipedalian Loquaciousness: Their dialogue at the end of the Genocide Run demonstrates a few cases of this (for instance, saying 'eradicate' instead of 'kill') coupled with a Creepy Monotone. The Neutral/Pacifist narration shows similar diction as well.
  • Sharing a Body: While the details aren't elaborated on, they probably do something along these lines to Frisk after they fall into the underground. They also explicitly pulled this with Asriel in the backstory, during the plan listed above. It didn't go too well.
  • Speak of the Devil: Referenced if you complete a consecutive Genocide run, calling themselves "The demon that comes when it is called." You actually do get to name them at the start of your game before you do anything else, which might be how you "call" them.
  • Spooky Photographs: Chara appears again in the True Pacifist Ending Credits if a Genocide run has been completed beforehand. If the protagonist decides that they have "places to go," the photograph after the credits will have the faces of Undertale's cast crossed out in red, except for Chara, who replaces Frisk. "THE END" appears in red, either implying that Chara has awoken and killed them all or to remind you of your Genocide run. This may also be a reference to the ending of The Shining.
  • Stepford Smiler: Implied to have been this in life, with everyone calling them the hope of the Underground, having been dearly beloved by the Dreemurrs, and Asgore describing them as having a hopeful look in their eyes, while at the same time they harbored some extremely dark secrets about their hatred of humans and why they climbed Mt. Ebott regardless on your take on their morality. It's also subtly hinted at if Chara is indeed the narrator, though you'd only notice it by comparing lines from different routes: the narration describes the bag of dog food as "half-full" in the Pacifist route, but if you kill just one monster, it becomes "half-empty" instead, suggesting that the narrator has a bleak outlook if you kill anyone — but odds are you won't notice because they'll keep the same lighthearted, snarky tone for all the other flavor text.
  • Stepford Snarker/Sad Clown: Possible explanations for them "laughing off" their poisoning of Asgore, that the poisoning was accidental and they tried to use humor to downplay the situation to cope with it.
  • Super-Powered Evil Side: By the time you get to Undyne the Undying, it's obvious that Frisk is not wining all these battles through sheer luck and pluck, there is something more powerful and (perhaps) more malevolent at work.
  • Symbiotic Possession: Possibly in the Neutral/Pacifist Routes.
    (after looking in the mirror in the Playable Epilogue): Still just you, (beat) Frisk.
  • Talk to the Fist: Beyond what the player does through the Genocide path, the Fallen will increasingly walk forward during conversations, engage in fights and strike enemies without any input from the player.
  • Terse Talker: Becomes one in the Genocide route. The save point text being reduced to "X left" and "Determination" is one of the more famous features of the route, but all of Chara's red text comes across this way.
  • Thanatos Gambit: The recollection of New Home's monsters would have you believe that the Fallen suddenly fell terminally ill. The truth is that the Fallen poisoned themselves and convinced Asriel into letting them share a body. It is unclear whether the goal really was just to get souls to break the barrier or kill everyone on the surface, but Asriel resists before anyone can come to harm and ends up mortally wounded in the process, dying not long after, and eventually being reborn as Flowey.
  • Took a Level in Jerkass: For the Genocide route. They already hated humanity, but now they're out to wipe out monsters too and eventually reality itself.
  • Took a Level in Kindness: For the Pacifist route, if they are believed to be the narrator or player. They may have hated humanity, but even though it would only take the monsters getting Frisk's soul for Asgore to unseal the barrier and declare war, they aid Frisk in saving everyone, monsters and humans, without a single person getting hurt.
  • Trademark Favorite Food: Chocolate. Toriel keeps a bar of it in her fridge out of sentimentality, and if you check Asgore's fridge at the end of the game the Fallen Child grouses that there isn't any... but only in the Genocide Run.
  • Troubling Unchildlike Behavior: It is largely unknown what they were like before their nightmare-inducing soulless Genocide incarnation. However, at five to thirteen years old (like Frisk, their age is ambiguous) they were, at the very least, a misanthrope with a chip on their shoulder for the people of their hometown, not to mention laughing off poisoning Asgore, if only by accident. They planned their own slow agonizing suicide via buttercup poisoning, convinced Asriel to assist with said suicide plan to fuse souls to pass through the barrier, and they were planning to kill at a minimum of six humans in their hometown for their souls. They also had a fixation with knives, with Toriel removing all of them from the house before Frisk's arrival, hinting that Chara had an affinity for harming themselves and/or others.
  • The Unfought: Despite debatably being the game's only genuinely villainous character and the cause for almost everything that went wrong, the only time you directly get to confront Chara is at the end of the No Mercy route, when it's far too late to fight them.
  • Vague Age: As with Frisk, we don't know how old they were when they fell into the Underground (or how much time has passed since they died, for that matter). They are only described as a child, meaning they could be anywhere between five and twelve years old.
  • Villains Out Shopping: If you believe the narrator theory and that they're also a villain, then the entire neutral/pacifist route turns into this, with Chara powerless to do anything except casually shoot the breeze with you until you decide to kill.
  • Was Once a Man: After their plan with Asriel failed, they're now a soulless entity akin to Flowey, but inside Frisk instead.
  • Well-Intentioned Extremist: If Chara cared about monsters, they were likely just a kid who found a loving family in the most unlikely of places after trying to "disappear" to Mt. Ebott, and wanted to destroy the barrier and free monsters. But this drove them to not only willingly sacrifice their own life even when it devastated their new family, they also planned to kill six other humans to take their souls and that they roped a reluctant Asriel into helping them kill themself and being the monster who'd absorb their soul and the others. That didn't work out the way they thought it would, and they ended up screwing things up in the worst way possible.
  • Wham Line: On the Genocide route, anything with red text.
    "Where are the knives."

    [looking in the mirror at both Toriel's and Asgore's houses] "It's me, Chara."
  • Where I Was Born and Razed: In the Genocide route, Chara ends up either possessing Frisk outright or assisting them to make the Underground go empty, killing off their own family in the process, and then completely erases the Underground itself along with the rest of the world. It's implied they've possessed Frisk to do it again at the end of a Soulless Pacifist run.note 
  • Wicked Cultured: Checking the Royal Guards in a Genocide route actually results in an alternate description which directly references a passage from an obscure Japanese novel. The quote is exact enough to seem to be deliberate from the Fallen's perspective, and uses the same first person pronouns as the rest of the altered text.
  • Woobie, Destroyer of Worlds: Possibly, depending on interpretations of their hatred of humanity and how they fit into the neutral and pacifist routes.
    • Asriel reveals he knows why they climbed Mt. Ebott, a place he knows is where people disappear never to return, but says only that it wasn't a very happy reason, then follows it up by telling Frisk Chara hated humanity, all with a pained expression on his face. Fans sympathetic to Chara take this to mean that Chara was mistreated as a child in some way by humans and, coupled with the fact that they committed suicide in the end and that in the Genocide route Flowey alludes to following in their footsteps by trying to erase himself from existence, that they went to Mt. Ebott wanting to die because of it.note 
    • The "narrator" theory holds it that it's your/Frisk's actions in pursuing the Genocide route that corrupts Chara from the snarky and friendly guide we get from other routes into the cold and power-hungry demon we meet at the end who believes the world is pointless and should be erased. This may be supported with Chara's own words, as they'll explain that they woke up confused about why they were back and say it was you who woke them up and your "guidance" (in hunting down every last monster in the Underground) that convinced that they were brought back for the sole purpose of gaining power by killing everyone.
  • Worthy Opponent: Strongly implied to consider Undyne one, describing her as "the heroine" in the Genocide run. Checking her in other routes has her similarly described by the gushing narrator as "the heroine that NEVER gives up" and sounding distinctly crestfallen over her slow disintegration if you kill her. Fan work and theories tend to expand on this, having the Fallen Child look up to her on Pacifist runs as well, and drawing explicit parallels between their attitudes towards humanity and her status as the only monster shown to naturally harness Determination.
  • Would Hurt a Child: The opening lines to Frisk's "fight" with the Monster Kid in the Genocide route is "In my way." And if you examine them, the description is "Looks like free EXP." Fortunately, Undyne intervenes.
  • Your Soul Is Mine: After killing everyone and destroying the world... it's the very last thing on Chara's wish-list. And Chara will get what they want too if you want to replay Undertale ever again after completing the Genocide route. This has profound implications on any further playthroughs you do decide to do.

    Dr. W.D. Gaster
The "Mysteryman" sprite commonly believed to be Gaster.

The man who speaks in hands. Dr. W.D. Gaster was the original royal scientist, before Dr. Alphys. Can't find him? Well, he didn't exist in the game at all for a while. Originally, if one were to explore the game's files, they'd come across a few odd NPCs, rooms, and messages that were cut. If a player decided to insert these aspects back into the game, what followed was the mysterious tale of a brilliant mind who invented a machine that accidentally caused him to be shattered across reality, with his fate uncertain. Even to this day, no one knows the complete story of W.D. Gaster... well, no one that wants to talk, anyway.

And note that the above instructions on how to activate him are in past tense because now you can access these previously cut elements randomly in the game without having to alter your game. A second Goner was also added in the Switch port, and a figure implied to be very close to him facilitated the reveal of Undertale's successor, Deltarune, with the game itself having a notable amount of nods to the mysterious scientist. As for what this means, however...

  • Ambiguously Related:
    • To the mysterious voice who unveiled Deltarune to the internet. While their manners of speech are near-identical, and the voice pointedly states that it thought we would find Deltarune "VERY, VERY INTERESTING," no official statement has been made.
    • To Sans, thanks to his Gasterblasters and scientific interests, with this often extending to Papyrus via proxy. Most fanworks depict him as either their third brother or creator/father, but the game is vague about their supposed relationship.
  • Ambiguous Situation:
    • Gaster's life was cut short, and he fell into his creation. But the followers never made clear if it was an accidental death because his experiment went wrong, or one on purpose after his experiment went wrong. One of the followers wonder if Alphys will end up the same way, which may be about her suicide in multiple neutral endings.
    • Although some go with the interpretation that he was made to literally have never existed, another interpretation of his fate is that people remember him, but simply don't talk about him anymore. Neither one has been confirmed or denied.
    • It is unknown if the Riverperson warning us about "the man who came from the other world" refers to Gaster. It could refer to Bonus Boss So Sorry due to his theme being named "wrong world", but if its talking about Gaster, what does it the mean that he came from the other world? Is this "world" related to Sans "I gave up trying to go back a long time ago", or just a way of talking about him shattered accross time and space? There is no answer to these questions.
  • And I Must Scream: You can find figments of him through the world lamenting his horrible fate.
  • Beyond the Impossible: His report mentions negative photon readings, which is a physical impossibility.
  • Body Horror: One of the NPCs who speaks of him is holding a miniature of his head, and his Mysteryman figment has two gashes on his face - one blinding his left eye, the other cutting into his mouth.
  • Dem Bones: The font Theme Naming convention he shares with Sans and Papyrus, as well as the appearance of the Mysteryman, heavily suggest that he is/was a skeleton monster.
  • The Dreaded: Along with his status as a once powerful scientist, he has many associations with the number 6, meta game mechanics, Determination, and general warnings to be wary of or avoid even speaking of him. Whoever Gaster was, it's possible he was, or is now, very dangerous. "Beware of the man who speaks in hands."
  • Dummied Out: An examination of the horrors of this trope. Gaster is lost through the game's files, unable to interact with anyone and aware that life goes on without him as if he's never existed. Players can search for him, but there's no way to help and so they can only wonder What Could Have Been if Gaster wasn't so unfortunate to be a cut character. A patch later made it so the Fun events work without needing to capitalize "fun" in the save file, but there're no new ways to interact with him yet. In addition, it seems that Gaster is very closely related to Grandpa Semi, a cut character whom little is known about.
  • Eldritch Abomination: He exists, yet he doesn't.
  • Expy:
    • The mysteryman sprite is modeled after Uboa. Just like Uboa, there's a hidden RNG dictating whether or not it'll show up.
    • Being a scientist stuck in a prison of his own making is similar to Dr. Andonuts in Toby Fox's The Halloween Hack.
  • Failure Is the Only Option: "You've all seen the happiest outcome. Neither of them could fix the machine, no matter how hard they tried. No one can."
  • Foil: In a sense, Gaster is very much an opposite of the Fallen Child.
    • They are both surrounded by an aura of mystery and vagueness, with very little known about them beyond what they offered to the underground. Chara provided them with hope, while Gaster provided the Core and presumably other creations.
    • The Fallen Child somehow ended up with Frisk and could be the greatest evil depending on the player's choice, and the story of Undertale resolves about the relationship of Chara and Asriel; Gaster simply vanished and his tale is not touched upon unless the player tempers with the game files, with only very few people remembering him: The Riverperson and presumably Sans.
    • The Fallen Child is remembered fondly by the Underground, with all of monsterkind lamenting their death alongside Asriel's. Gaster is feared, with the Riverperson telling us to "beware of the man who speaks in hands".
    • Lastly, Chara was a normal human child before their death. Gaster was a genius monster before his life was cut short. They both became something else.
  • The Ghost: His existence is only vaguely hinted at through the game. Dr. Gaster was the previous royal scientist before Alphys, but his experiments have gotten him shattered across the time-space continuum. His predicament is so bad that players originally learned about him by fixing a "typo" in the game's save file (Changing the "fun" item to "Fun" and setting it to certain values. After a patch, changing it became unnecessary.) and then trying to puzzle it out through data mining and trial and error.
  • Ghostly Gape: One of his figments (serving as his folder's image) looks like it might be a skeleton like Sans and Papyrus, but with that particular expression and the cracks on his face, it ends up looking more like a ghost. Given his predicament, it's probably fitting.
  • Gone Horribly Right: It's a common headcanon that his machine was created to solve the problem of the Barrier, but whatever timespace shenanigans it would have used to remove it ended up affecting him instead.
  • Gone Horribly Wrong: As brilliant as he was, his life was cut short; one day, his experiments went wrong, he fell into his own creation, and... poof.
  • Hoist by His Own Petard: Non-villainous version. Gaster was the one who designed and built the Core, providing the Underground with electricity. Unfortunately, an accident caused him to plummet into one of his creations - presumably either the Core or Sans' broken machine - the damage of which was so severe that it blasted him and possibly some of his colleagues across time and space.
  • It's a Wonderful Plot: For poor Dr. Gaster, this trope appears to have gone horribly wrong; one of his grey figments asks the player about the prospect of a world where everything is exactly the same except you don't exist, everything functioning perfectly without you. What's worse is that he wasn't erased from history, and yet life still went on; one might assume that nobody mourned. And it even seems to be worse than that. Other NPCs needed to be coded back into the game to get any information on him. Whatever happened was so bad it did the same to anyone who knew much about him... except for one being: Sans, who wields weapons named after him, is implied to have researched a supposed anomaly messing with timelines alongside him, and may or may not be related to him in some way or another.
  • Leitmotif: "Gaster's Theme", a song that can only be heard in a secret Sound Test screen that only features a few apparently unused songs and locks up once the player give "feedback" by listening to it. Fittingly enough, the vessel survey that opens Deltarune plays a remix of his theme.
  • Meaningful Name: Named after the Wingdings font, which he uses to speak and write. Much like the man himself, Wingdings is cryptic and mysterious, and it takes a lot of effort to memorize and understand. "Gaster" probably comes from the Old English word "gast," from which the word "ghost" derives. "Aster" is also the name of a typeface and is a genus of flowers. In the game, Sans snores in Zs that look close to the Aster font instead of the usual Comic Sans, but that only raises more questions.
  • The Missingno.: His existence is an exploration of this trope, and what such a character would be like within the context of the game world itself.
  • Morally Ambiguous Doctorate: He's a rather ominous doctor, between his dangerous creations and the fear of those NPCs which discuss him.
  • Number of the Beast: There is data in the game for a possible battle encounter against Gaster. For some reason or other, his attributes have the number 6 in every digit. 66 being the Fun value that specifically reveals the door to Mysteryman's room at Waterfall is one factor that plays into fans assuming he is what Gaster looks like.
  • The Omnipresent: He's been scattered across space and time. And he seems to be able to eavesdrop on everything.
  • Production Foreshadowing: His existence in Undertale supposedly is meant to foreshadow the existence of Deltarune. The secret room 272 with the mysterious figure that says "redacted" in wingdings leads to a Sound Test, and the moment you put Gaster's theme, it will say "thank you for your feedback! Be seeing you soon!", which lead to Deltarune supposed connection with a mysterious voice who was waiting for us.
  • The Professor: A tall skeleton(?) with a goofy grin who speaks entirely in Wingdings. Also the most brilliant mind in all of monsterkind.
  • Ret-Gone: Apparently, whatever fate befell Gaster took his history with it, as even learning his name requires extreme luck and/or messing with the code.
  • Riddle for the Ages: While there are some "models" of Gaster that are more popular in fanon interpretation, at the end of the day, he as a character is an absolute mystery on just about every level. We have no idea what he was like as a person, what his goals or relationships were, or even his exact fate and how it befell him; all that is known for certain about him is his former role as the royal scientist, the fact that he no longer properly exists and likely never will again, and the fact that he has some kind of important connection with Sans.
  • Tempting Fate: One of the grey NPCs that explains the story behind Gaster says he has nothing to fear from him, since he has a piece of him. He vanishes immediately after he's done talking. A notable case because none of the other grey NPCs disappear until you leave their rooms... and because his disappearance is accompanied by the exact same sound that plays when Gaster himself (or, at least, whatever apparition serves as his image shown above) vanishes, too.
  • The Unintelligible: Like Sans and Papyrus, Gaster speaks in the font he is named after - in this case, Wingdings, which... probably isn't a "dialect" the player will understand. Fortunately, lots of translation tools exist online.
  • The Un-Reveal: It's never explicitly stated which of Gaster's creations caused him to become scattered across space and time. Possible canditates are the CORE, the Determination Extractornote  and the mysterious machine hidden in Sans' basement.
  • Vagueness Is Coming: Among Alphys' reports, there is the elusive Entry #17 in which Gaster talks about doing research on an ever expanding darkness. He then asks what two unknown people think about it.
  • Voice Grunting: The oddest sounding variety of it in the game: a jumble of random text-to-speech programs speaking in gibberish, only heard in the hidden Entry #17. They're actually fragments of a text-to-speech message from Toby Fox asking players not to spoil the game's secrets. The "Version 1.01" patch replaced the message with a bunch of text-to-speech voices laughing, one after the other, which sounds pretty much the same when jumbled up.
  • Wham Line: His followers all speak of Gaster in the past tense, and the snippets of his story you hear all imply that he's dead, gone, or Ret Goned. That is, until you speak to follower #3, whose final line suggests something much stranger:
    "Well, I needn't gossip. After all, it's rude to talk about someone who's listening."
    • Similarly, there's the final line of Entry #17, which implies...well, it implies something, alright:
      "...what do you two think?"

    Gaster's Followers and Goners 

"However, his life... was cut short."

A group of characters that are all related to the game's internal "Fun" value, there are five characters total: Gaster Followers 1-3, "Goner Kid" and Goner Clam Girl. The former three directly talk about W.D. Gaster himself, and while the latter two never talk about Gaster directly, they're usually lumped together with the other three for the sake of simplicity (and they can only appear at a certain Fun value). What's notable about these characters as well is that, if the player leaves the room that they appear in, they will always disappear. Except for Gaster Follower 2 and Goner Clam Girl, who literally disappear right in front of the player's eyes after finishing their sentence.

Tropes that apply in general

  • Ambiguous Gender: With the exception of Goner Clam Girl, they are never given a canon gender. Most players assume "Goner Kid" is female because of how it looks like it's wearing a bow, compared to Monster Kid's having horns.
  • And I Must Scream: Like Gaster, none of them appear in the game itself without altering the game's coding until the 1.0.1 patch, where they can appear randomly.
  • Deliberately Monochrome: All five of them are grey.
  • The Last of These Is Not Like the Others:
    • Unlike the rest of the followers, Gaster Follower 3 is not a Palette Swap of an already existing NPC. However, it receives a "normal" counterpart in Deltarune, portrayed as a hunched-over bird.
    • The Clam Girl transforms into her goner counterpart, rather than existing separately from her.
  • No Name Given: None of them have received names.
  • Palette Swap: Gaster Followers 1-2, "Goner Kid" and Goner Clam Girl are all palette swaps of several of the preexisting monster characters. Notable in that, despite being palette swaps, they all have notable differences from the "normal" versions.
    • "Goner Kid" = Monster Kid
    • Gaster Follower 1 = The ficus licker in MTT Resort
    • Gaster Follower 2 = The monster holding the donut at the Spider Bake Sale
    • Goner Clam Girl = The Clam Girl near Napstablook's house
    • Gaster Follower 3 also turns out to be a palette swap. ...of an NPC who appears during the Playable Epilogue of the sequel. You can find them in the library while walking around the town.

Tropes that apply to Gaster Followers

  • Body Horror: Follower 3's normal appearance is revealed in Deltarune, but given their differences it seems as if the follower has lost their lower jaw, had their throat cut and their feet melted into the floor.
  • Mr. Exposition: All three of the Gaster Followers only talk about what happened to W.D. Gaster in some form.
  • Oracular Head: The "head" in Gaster Follower 2's hand is the one talking.
  • Properly Paranoid: Gaster Follower 3 believes it'd be "rude to talk about someone who's listening" in regards to Gaster. It might not be paranoia given that Gaster Follower 2 holds "a piece of" Gaster.
  • Rhymes on a Dime: Gaster Follower 2 does this if you look closely.
    Gaster Follower 2: Alphys might work faster. But the old Royal Scientist, Doctor W.D. Gaster?
    One day, he vanished without a trace.
    They say he shattered across time and space.
    Ha Ha... how can I say so without fear?
    I'm holding a piece of him right here.
  • Satellite Character: To Dr. Gaster, as they are only there to provide information about him. They might also be the persons pictured on the photographs in Sans' basement, but that is just speculation.

Tropes that apply to Goners

  • Connected All Along: The Switch version reveals that the Clam Girl can transform into her goner counterpart, suggesting that she has some connection to "Goner Kid."
  • The Ghost: Suzy, the Clam Girl's neighbor's daughter. As of the Switch update, the Clam Girl hints you might meet her soon. This is seemingly Production Foreshadowing for Deltarune, where Susie appears as a deutoragonist.
  • Monochromatic Eyes: "Goner Kid" has completely blank eyes.
  • Surprise Creepy: The Clam Girl, when she transforms into her goner counterpart, appears with a single, bloodshot eye in place of her head.
  • Tomato Surprise: As of the Switch update, the Clam Girl transforms into her goner counterpart, if you find her after a Pacifist run.
    Clam Girl: So you never met my neighbor's daughter.note 
    But please don't despair.
    Because the time that you will meet her...
    [Music stops.]
    * ... is fast approaching.note 
  • Unknown Character: The Clam Girl's neighbor and the parent (Gender is never specified) of Suzy. No information is about them has been revealed, for all we know they could be just an Invented Individual. We do meet Susie in Deltarune, but we haven't gotten any information on Susie's family yet.


How well does it match the trope?

Example of:


Media sources: