Note: This AU may contain some swearing due to Underfell being an edgy Alternate Universe.

Sans Character Information Full Name Sans/Underfell Aliases Fell

Edge LordEdgyLazy A** (By Fell Papyrus)Useless (by Fell Papyrus)weak (by Fell Papyrus)little meow meow (by ink!sans)

EdgeLordEdgeRedNega Sans PepperRustleDog

"I'm going to have ONE HELL OF A TIME!!!" – Fell Sans' Canon Quote

Fell Sans, is one of the main characters of the Underfell AU and the brother of Papyrus and takes on a similar appearance to the Sans of Undertale. Sans is a skeleton, who is pushed around by his younger (albeit significantly larger and more durable) brother Papyrus. One difference about Underfell Sans is that his eye glows red.

In the past, Sans worked with Gaster and Alphys as royal scientists

Then at some point in the past, Sans was about to have his skull crushed by Asgore but was stopped by papyrus, and impressed by his speed and bravery he told papyrus that in most cases he would have had him punished severely for his heroism, but instead offers a job in the royal guard. Asgore tells him that if he does so, his brother will be left alone, and so he agrees to only being grabbed by Asgore, saying that his act of defiance would not go unpunished. He carved 2 scars into papyrus, and enraged, sans made several attacks but was stopped by papyrus, enraged that sans had such abilities but only did anything until after Asgore was finished. Sans kills some monsters on laboratory to protect himself and Papyrus. (link)

Underfell Sans looks very similar to his Undertale counterpart. He is a skeleton with sharp teeth, with one being gold. Sans's red eye shows to reflect how “corrupt” (mainly emotionally hopeless) he’s gotten, so when it flickers, it would be yellow and orange. Sans holds in a lot of emotional stress, so he’s constantly radiating his powers and eye 24/7, which mostly affects his jacket fur.

He wears a black winter jacket with a jacket fur flame hood and a gray cotton hoodie, and a red sweater with a golden chain with black pants that have yellow stripes going down. He wears red shoes with yellow socks. Sans wears a black jacket, with the "fluff" at the collar being notably more ruffled than the original Sans'. His shirt is a red color in contrast to the normal white shirt. His shorts have a yellow strip instead of a white one and he wears black/red/white shoes or red slippers, as opposed to his counterpart's light blue slippers. His body structure appears the same as his counterpart (besides his teeth).

Fell Sans, much like every other monster in Underfell, is a darker and edgier version of the original Sans.

Sans can be harsh at times. He is not into puns that much, but he likes knock knock jokes. He often gets tired, but not flustered. He has an allergy to cats. He strives to be cool and collected.

Fell Sans makes appearances in both of the UnderTale Comics, where Sans appears as one of the three bosses along with UnderFell Papyrus and Asgore.

Sans is a little more powerful than his UnderTale counterpart. He can manipulate bones and can move a living soul at ease with telekinesis and Gaster Blasters. He can Teleport just like his UnderTale Counterpart. The bones and his Gaster Blasters he summons are red. He can use orange and sharp bones.

Judgement Hall - In the True Pacifist timeline, Sans keeps an eye on Frisk. He hates how Frisk keeps being nice and waits at the Judgement Hall. This fight would be similar to the boss fight in UnderTale, only more brutal, harder and deadly. Once Frisk managed to 'reform' Sans, he refuses to fight anymore.

Paciist route:

Sans has a personal hatred for Frisk and wants nothing more than to kill them. After their encounter in Judgement Hall, Frisk managed to 'reform' Sans. Sans then said he wouldn't harm Frisk any longer, as he now sees the purpose from what they have been doing since their arrival.

Genocide route:

Sans first assumes that Frisk is weak and will eventually be killed. After losing his brother, Sans becomes "broken". He doesn't feel hatred since, in this world, monsters follow the motto "kill or be killed." Sans then goes to the Judgement Hall and waits for Frisk. Instead of fighting or threatening Frisk, he instead thanks Frisk for believing in the motto. Sans is reluctant to fight Frisk because of how powerful Frisk became. Sans tries to calm Frisk down but to no avail. When it is clear that Frisk will not back down, Sans begins to fight with his full strength, but in the end, Sans dies after 24 rounds. During the fight, Sans loses his fear of Frisk and comes to terms with his imminent death. (Fanon) Some fangames show that Underfell Sans breaking the game rules and kills Frisk every end of fight to don't let the Genocide route will be finished.

Sans feels responsible AND guilty about the outcome of both their lives, feeling useless and can’t bare that he can’t be the one to protect his little brother anymore because he feels like Papyrus doesn’t want him to. Nonetheless he remains distant, but close enough to be there when Papyrus is in serious danger. Both Sans and Papyrus try really hard to be the “ mature/cool/collected brother ” of the two . So there’s a lot of fighting (not in a very violent way) or being sarcastic towards each other. They don’t hate each other at all, In fact really careing about each other! It’s sort of that “ ugh FINE “ relationship. They also don’t talk about how they feel or what’s bothering them either. Sans is the one that puts the distance between them from having a stronger sibling bond (link)

Sans hates Flowey because of his Frailty.