Undertale AU Wiki
* For the character's more in-depth information, see:
* But nobody came.

* This article contains information that is from a cancelled AU, an AU that has been put on an "Indefinite Hiatus", or an AU that has not had a story update in a year. As such, some information here may not be found in any established story, and could be considered non-canon.

Time of Last Story Update: May 18th, 2016

Time of Cancellation: November 8th, 2018

Undertale - Savepoint.gif
* (Seeing an article of an AU you can freely make content for...)

* (It fills you with determination.)

This article is about an AU that has been deemed community-shared, either by the author declaring it, or from long-term abandonment by the author. For elaborated information on community AUs, see the Templates policy page.

*kid, listen. there are spoilers on this page; be careful when you're reading.

*you don't want a bad time, do ya?

To access just the story, click here.

For the prequel, see Aftertale.

Errortale (or Ask Error!Sans) is an AU created by Tumblr user Loverofpiggies. It was created on December 28th, 2015. The story takes place on the askerrorsans blog, where anonymous users or normal users progress the plot by asking Error questions. It starts off simple enough but then tells the tale of how he kidnapped Swap Sans in a genocide battle against Underswap Papyrus. So Swap Sans is there to answer questions as well as the plot continues to progress.

On November 8th, 2018, CQ tells certain plot points that would've happened or been confirmed in the askerrorsans canon. Some include that Errortale is a Sequel to Aftertale, and that Error is an older version of Geno. Another point that is confirmed was that Blue was going to get corrupted into an error, and would be transformed into Blueberror. Other info is included in the post.


Error Sans (Post Geno)

Error is a version of Aftertale Sans (Geno) that messes around with dangerous determination magic, even with warnings from Sans. He eventually accidentally sends himself to the anti-void. To which, in his final moments of sanity, he's furious that even though he got his happy ending, this had to happen. Geno lost his sanity to hating everyone and anyone except for himself, which is why Error is so hateful and calls everyone 'glitches' or 'abominations'

In the present, Error is a black glitchy skeleton with a color palette mainly consisting of dark reds/reds, dark blues/blues, yellows, oranges, and blacks. He has two unsymmetrical eyes, one a small yellow pupil and the other is a circle with yellow, blue and black. He usually needs to wear glasses because of his eyes being messed up from when he was Geno but refuses to wear them sometimes. He wears a black hoodie, a red shirt, black shorts with stitches holding it, and black slippers. He has blue wires tied to his fingers.

He has a selfish and playful personality and thinks he's helping out the multiverse. He steals things, raids and destroys AUs to name a few things he does. He loves to play jokes, and make snarky teases at his enemies. Canonically, he doesn't get mad until things don't go his way, how he expected it to happen, or when others trigger one of his fears.

Underswap Sans (Blueberry)

Underswap Sans (or called Blueberry/Blue) is an eccentric personality that only wishes the best for people. He is a pacifist and always tries to go for a route of mercy or kindness. Which completely conflicts with Errors merciless and snarky personality. Blue, however, is not naïve from this and is well aware that Error acts like a selfish prick. Instead of getting angry at him though, he simply sends him the same mercy as he does for everyone else. He even goes as far as to touch him, which triggers his haphephobia and causes Error to crash.

He is a bright white skeleton with a palette mainly consisting of navy blues/blues, greys, whites and golds. He has blue eyes that usually have stars, and wears shoulder pads, a grey shirt, blue pants tucked into navy blue boots. He also wears a cape that is tied in the front. He has hopes of capturing a human someday, but that dream was interrupted when Error took him into the anti-void and eventually abandoned him there.

Underswap Papyrus

Underswap Papyrus is Underswap Sans' brother (Blue). He is the one that Error fought with to rescue Blue from being kidnapped after Error completely wiped Papyrus' AU of all the monsters. Having a battle where he tried to get Error to stop using Blue as a puppet, as Error was making Blue fight for him. Eventually losing the battle and losing his brother, and is canonly on a search for him in the Omega Timeline after CORE!Frisk picks him up.

Underswap is a tall, lazy white skeleton that has a palette consisting of oranges, greys and blacks. Wearing a Orange hoodie, black shorts, and grey sneakers. Although his outward attitude may seem that he's carefree, he actually cares deeply for his brother and will fight for his life.


For more information, see CORETale.

CORE Frisk is a monochromatic version of Frisk that was pushed into the CORE, and was separated and scattered, similar to Gaster's fate. Due to their powers, instead of being wiped from existence altogether, becomes an omnipresent character who is aware of all timelines. Now, they hold the guardian role of the Omega Timeline and recruit people or monsters with no homes there.

In this comic, CORE makes an agreement to help Papyrus find their brother and informs him of how powerful Error really is. Giving Papyrus granted access to the Omega Timeline to start his search alongside CORE.


Error Papyrus is rumored to be Errors brother, though it is never confirmed. He also looks similar to Error with the color palette and physical traits, but nothing much else. This one-time character appearance doesn't show much about who this character is. They seem to have a softer version of Errors personality, but still selfish.


Error Undyne is also rumored to be related to Error in some way, but like stated above, it is never confirmed. Just like the same with Error and Error Papyrus, they have the same color palette and the same glitchy traits, but nothing else. Meanwhile, Undyne has more of an aggressive version of Errors personality. She does not play around or tell jokes and seemingly doesn't hesitate.


  • Even though Error was made in December, his canon birthday is April 4th. Sprouting from the 'ERROR 404' Joke.
  • Error has Haphephobia, the fear of being touched.
  • Error is canonly Nearsighted, and he wears glasses to help his sight.
  • During the Underswap fight scene, Error talks about Underswap's existence being only by 1 divided by 9,109,043,495 probable. This equation equals 0.0000000081%. Only an 81 hundred-billionth chance of being able to exist.
  • Error once tried to destroy UnderSwap, but he "ran into a problem."
  • He has multiple interests that are shown in the comic, such as crochet, playing with puppets, telling stories and examining codes of different AUs.
  • Error, Fresh, and Geno are not actually brothers. This joke was coined from the fact that CQ made all three sanses, there's even a comic series based around this premise. But it never will actually be canon.
  • On the November 8th post, It was also stated that Errortale would have a big video describing its plot, and then never be touched again. So the comic is technically canceled.
  • He is often shipped with Fresh, or Ink. CQ even encourages or teases these ships, but they will never be canon.