Error sans

An Alternative Universe (AU) is a branch of an official storyline or concept that develops alternate versions of events, placing characters in diverse settings and situations, granting them abilities, and so on. Thus, the stories and characters of Undertale have AUs based on them. The entire diversity of Alternative Universes is called the Multiverse.

The soul is a vital part of every character; it's the only way to live. Almost all souls are heart-shaped (sometimes star-shaped for special characters, etc.). Most souls are white, as they are secondary characters (regular villagers, humans, and monsters). Players can have different soul colors, with seven in total, each representing a different meaning:
Red - determination.
Blue - patience.
Orange - courage.
Blue is decency.
Purple - persistence.
Green - kindness.
Yellow is justice.

The Doodlesphere is Ink's personal space where he keeps track of the universes.
This is a boundless space, representing the entire multiverse. It is filled with large floating buckets of paint, representing other universes, and the contents within them serve as portals, as well as being gravity-free. Within the sphere are large floating doors, each representing a separate world. They function as portals, allowing characters to travel between worlds.

Anti-emptiness is an unlimited empty white space.
Some features:
There are no shadows or sounds in it, and it is impossible to determine direction and distance.
In the Anti-Void, the need for food disappears, although consumption of food is still possible.
Above the surface where the monsters that enter it walk, Error's intertwined threads hang, where he stores his dolls and the souls of the people he killed. There are no other items in the Anti-Void, so Error must steal them from the Underfell.

Known as: Error
Original name: Geno
Species: Skeleton Monster
Gender: Male
Orientation: Aroas
Height: Same as classic Sans
Phobias: Haptophobia
Likes: Undernovela, playing with dolls
Dislikes: Underlust
Occupation: Destroying errors in his opinion
A twenty-one-year-old black skeletal monster with blue teardrop-like markings running from his eyes to his chin. He has multiple tongues in his mouth. Occupation: Destroying errors (characters), in his opinion. Haptophobe (fear of being touched).
He wears a black jacket with blue patterns on the sleeves and a red sweater underneath.
Wide black pants. A long blue scarf. Mismatched black sandals. He has poor eyesight. Error is a psychopath and a hypocrite, but if you try, you can befriend him. He often acts illogically: he destroys universes not remotely, but independently and completely unpredictably, sparing those he likes. He often has emotional outbursts.
The left pupil is completely white, and the right one is yellow. The whites of the eyes are red.
Abilities: Wields blasters and bones; He also possesses threads—a concentrated version of telekinetic magic—which he can extract from his eyes and hands. These allow him to extract souls from their bodies, move them, and destroy them. Error primarily uses them for personal purposes; Using captured souls, Error can see through their eyes;
Capable of opening portals to other universes, which can be one-way or two-way, and also show Error's past;
Capable of studying the code of other universes.
Because he's an error, he constantly glitches, both physically and vocally. White "Error" signs hover around him.
When he is embarrassed, afraid or angry, he becomes more vocal and can “reboot”.
His greatest enemy is Ink. Because he, on the contrary, protects the AU and creates more universes. But now they have a truce.
Error loves: chocolate, cats, sewing dolls of different characters, the TV series "Andernavella"

Error is a psychopath and a hypocrite. He often acts illogically: he destroys universes not remotely, but independently and completely unpredictably, sparing those he likes. He often has emotional outbursts. Error's main goal is to destroy all anomalies and glitches, even going so far as to destroy original/canon universes. He will call anyone or anything a glitch or a mistake simply because he doesn't like it, and then calmly kill them. Error also wants to destroy all universes, leaving only one, but he doesn't know which one. In his free time, Error observes other universes or plays with dolls in his Anti-Void. He also had a friend, DarkBlitz08, a person with a green soul, who turned out to be a hallucination.

Has blasters and bones;
He also possesses threads—a concentrated version of telekinetic magic—that he can draw from his eyes and hands. They allow him to extract the soul from the body, move it, and destroy it. Error primarily uses them for personal purposes;
Using the captured souls, Error can see through their eyes;
Capable of destroying entire universes without even entering them. However, he still enters and attacks everyone, as he prefers the long way around;
Capable of opening portals to other universes, which can be one-way or two-way, and also show Error's past;
Capable of manipulating the Anti-Void code and studying the code of other universes;
Capable of turning captured Sanses into dolls, which was confirmed by a fanfic that the author made canonical;
His special attack can destroy all universes one by one at incredible speed. He has only used it once and doesn't plan to do it again;
As a mistake, can hear aski;
As an error, it does not obey the rules of any universe.

Main article: Errortale
Following the events of Aftertale, Geno, despite Sans's pleas, uses the power of Determination and accidentally sends himself into the Anti-Void. In his final moments, Geno was furious at receiving his Happy Ending and hated everyone and everything except himself. Afterward, Geno's appearance changed and he became Error.

Ink is a skeleton who is the guardian of the multiverse. He's a mischievous prankster. A funny guy. But he doesn't really care about other characters. He literally has no soul, and to experience emotion, he drinks paint from the bottles on the belt hanging from his chest.

Dream is a bundle of energy in a skeletal body, the keeper of positive emotions. He is 500 years old and has a brother, Nightmare, with whom he has not spoken for a long time and is at odds, although he still loves him. Dream is composed entirely of positive feelings, his soul is a golden apple, he treats everyone with kindness, even his brother. Abilities: bow and arrows. His personality is quite childlike, since he spent 494 years in stone because of Nightmare, and therefore his growth has stopped, and he remains the same as a child. However, he is not so naive or weak. His image consists of a black suit with black gloves, over which he wears regular yellow gloves, and yellow boots with green ribbons. A yellow cape/vest. On the strap are the initials [DS].

Swap is an energetic and cheerful skeleton with short blue hair.
He is the royal guardian of his universe. He is kind and always ready to help.

Nightmare is a skeletal monster, the keeper of negative emotions, and Dream's brother, whom he hates. He is cruel, cold, and merciless. He is the one who spreads negativity throughout the multiverse. Whenever someone is struggling in life, he cunningly persuades them, offering them something in exchange for what they want. His body is completely covered in a black liquid—negativity—and four long tentacles protrude from his back.

Cross is a skeletal monster dressed in black shorts and a white jacket. He's serious, reserved, yet kind. His AU was erased, and when he asked his friend Ink for help, Ink said he couldn't revive the dead.