Underfell is a Fan Verse of the popular video game Undertale, which originated on Tumblr in late 2015. The original blog can be found here
, while the creator's personal blog can be found here.
At its heart, Underfell follows the formula of a traditional Mirror Universe, in which the moralities of the heroes and villains are flipped. Examples include: Flowey (still with his soul) being Frisk's grumpy protector and guide in the Underground, Toriel as an unstable (platonic) yandere to the human children who will attempt to kill any who want to leave her, Papyrus as a wannabe villain rather than a hero, and so on. The notable exception is usually Frisk, who tends to retain their normal heroic fanon personality.
Underfell was first and foremost created as a design aesthetic, so there wasn't a real canon backstory to the characters outside of the idea that they were an alternative, evil version of themselves. However as its popularity increased and it spread to other online communities such as Pixiv and Archive of Our Own, certain widely accepted headcanons and tropes began to emerge.
There tend to be two main interpretations of the AU as a whole: it's either played straight as a traditional Darker and Edgier mirror universe, or portrayed as a tongue-in-cheek, over the top "edgy" verse. The original creator seemed to lean into the latter, though they were fine with others taking their verse more seriously.
As a Fan Verse, anyone in the community can contribute their own stories to the AU. Aside from the vague mirror aspect of the characters, the story and setting of the universe is wholly open to interpretation. As such, many aspects of the universe may change drastically from work to work. While some may hold the original creator’s vision to be the definitive version of the universe, many others see it as a template to grow upon and create their own interpretation of the world of Underfell, something the original creator is aware of and is fine with.
One of the best known pieces of fan work for this particular verse is an on-going fan comic by Kaitogirl. You can read it here or here and watch a dub of it here.
Has a wiki here, an entry on the Undertale fan verse wiki here and a subreddit here.
This AU in general provides examples of:
- Abusive Parents:
- The Dreemurrs were not good parents in this verse. At best they are overly concerned with raising Asriel to be a ruthless king and warrior. At worst they make their kids' lives a misery and Asgore murders Chara for their soul power.
- Gaster to Sans and Papyrus if he's their father. Sometimes Sans even throws him into the core to get rid of him when his treatment of them gets too bad.
- Adaptational Heroism:
- Flowey keeps his soul and so retains Asriel's morality. He acts as Frisk's reluctant guide and protector as they journey through the Underground.
- Chara was a sweet kid who never wanted to kill anyone, human or monster.
- Humans take the role of the peaceful race who were attacked by monsters.
- Adaptational Villainy: Almost everyone who isn't Frisk, Flowey or Chara. The entire monster race could just count by itself.
- Alternate Self: Everyone, main characters and NPCs, except Frisk. They are usually the same human child as in canon, who just happened to fall into a much darker Underground.
- Alternate Universe: One with the main premise of peaceful humans and evil monsters.
- Archnemesis Dad: Asgore to Asriel if the latter pulls a Heel–Face Turn.
- Aw, Look! They Really Do Love Each Other:
- Sans and Papyrus usually still care about each other even in the darkest versions of this verse. Papyrus sometimes gets his scar defending Sans from Asgore.
- The Dreemurr family, particularly if Asgore didn't poison Chara and actually tried to be a father to them. At the very least, Asriel usually loves Chara genuinely even if he does pick on them.
- Beware the Nice Ones: Humanity may not have attacked the monsters like in canon, but they still sealed them Underground to end the war.
- Beware the Silly Ones:
- Papyrus doesn't hold back any in his battle with Frisk, making the fight far more difficult. Sometimes he'll pull out his Gaster Blasters, which kicks it up to eleven.
- Any of the sillier, goofier monsters thanks to monsterkind as a whole being much more vicious and eager to kill humans.
- Big Bad: Usually it's either Asgore or Sans who take the place of Photoshop Flowey and/or Asriel as the final enemy Frisk and co. have to face in the Underground.
- Big Good: Photoshop Flowey and, later, Asriel in his restored form.
- Blood Knight: Undyne, even moreso than in canon. Tends to be part of her role as The Brute.
- Bullying a Dragon: Why oh why did Asgore think attacking humanity was a good idea?
- Calling the Old Man Out: Asriel to both his parents but Asgore in particular. See Hates Their Parent.
- Creepy Good: Chara, if they keep their Creepy Child aesthetic.
- Crossover: Happens frequently with other popular Undertale fan verses, such as Underswap and Storyshift. Sans and Papyrus in particular meet their alternative selves an awful lot.
- Dark Is Evil: The monsters, especially with their Red and Black and Evil All Over designs. Just how evil they are varies.
- Dark Is Not Evil: If the monsters are all Minion with an F in Evil level villains.
- Darker and Edgier: And how! Whether taken seriously or played for laughs, this is the entire point of this AU.
- Depending on the Author: Naturally since this is a Fan Verse that anyone can create content for.
- The Dragon: Undyne towards Big Bad Asgore.
- Evil Matriarch: Toriel. Particularly if she's still the power behind the throne.
- Extreme Doormat: Chara, sometimes, taking on the role while Asriel takes on the role of Big Brother Bully.
- Fan Verse: Yep. It's all an alternate dimension AU which incorporates both Mirror Universe and a few Swapped Roles aspects.
- God Save Us from the Queen!: Toriel before she left for the Ruins.
- Goldfish Poop Gang: Papyrus in more lighthearted versions where he can't bring himself to fight Frisk for real and instead just chases them without actually attacking.
- Hates Their Parent: Asriel. Sometimes from the beginning, sometimes post Heel–Face Turn. The latter often happening when he finds out Asgore murdered Chara.
- Knight in Sour Armor:
- Flowey is a sour cynic with Jade-Colored Glasses who still wants to protect Frisk and help them escape the Underground.
- Sans, sometimes. If he's not apathetic towards Frisk or trying to kill them, he'll often take on the role of Frisk's hidden protector or even Big Good.
- Lonely Rich Kid: Asriel, at least until Chara fell into the Underground. See Only Friend.
- Mad Scientist:
- Alphys has far fewer ethics here than she does normally. Sometimes she goes so far as to make the Amalgamates on purpose.
- And sometimes she's following in Gaster's example.
- Mirror Universe: The entire premise is that everyone who was good is now bad and vice versa, with the exception of Frisk.
- Morality Pet:
- Chara to Asriel and, later, Frisk to Flowey.
- Frisk to the whole Underground if they end up befriending them.
- Offing the Offspring:
- Asgore poisoning Chara to try and take their soul.
- Often it will be Toriel who killed the other fallen children for trying to leave her.
- Only Friend:
- Flowey to Frisk. In more heartwarming takes, this doesn't last and Frisk eventually befriends the monsters as they can do in canon. It just takes longer.
- Asriel and Chara like in canon, but for different reasons. Usually because Asriel is The Bully and the other monster children disliked him, feared him, or both.
- Only Sane Man: Flowey for the heroes and Sans for the villains. Both tend to be the savvy, pragmatic voices of reason to the idealistic Frisk and the over the top villainous monsters, respectively.
- Token Good Teammate: If Sans still made a promise to Toriel to not kill any humans that leave the Ruins, Sans will fall into this role for the monsters' side. That said, it's still possible for Good Is Not Nice to apply and he probably won't stick his neck out for Frisk, just simply not go out of his way to harm them either.
- Perpetual Frowner: Flowey as the direct opposite of his canon self.
- Red and Black and Evil All Over: Oh so, so much. There's a reason this verse is jokingly referred to as the "Hot Topic of Undertale AUs."
- Red Eyes, Take Warning: A lot of the monsters have red eyes to match their overhauled red and black color schemes.
- Symbiotic Possession: Chara and Frisk working together instead of Chara forcing Frisk to kill.
- Underestimating Badassery: Frisk, Chara and humanity in general are still just as powerful compared to monsters as in canon. The monsters being more bloodthirsty and eager to fight doesn't change this (it does canonically make them stronger, but not by nearly enough to close the gap), something they realized far too late after attacking humanity and being soundly defeated. In the present, the only reason every fight doesn't end in a Curb-Stomp Battle is that Frisk refuses to fight back.
- What If?: What if the monsters were Always Chaotic Evil?
- White Sheep:
- The gentle, heroic Chara to the dark, evil Dreemurrs.
- If Chara is evil themselves, Flowey takes the role instead after his Heel–Face Turn.
- Why Don't You Just Shoot Him?: Sans sometimes suggests Papyrus just ambush Frisk and kill them with a ranged attack. Papyrus is appropriately disgusted and insists they need to do it the "right" way: through death traps and trickery.
