Error!Sans is an AU destroyer bent on destroying all AUs and things he considers 'glitches' or 'mistakes' in the multiverse. He uses blue strings to tie up and shatter souls. If the strings go inside a victim, he will be able to transfer his soul into the victim, controlling them to do whatever he likes, leaving the victim helpless. He can jump from one universe to another, as well as having several other glitch powers/quirks. Error used to be Geno Sans. Yet during his time in the surface, he had began to play around with his DETERMINATION, despite Sans telling him to stop doing so. Finally, Geno had accidentally sent himself to an empty and endless place where time was non-existent. He quickly began to grow insane, the emptiness and the loneliness eating up at his sanity and his anger towards everything (and everyone he had helped) shaped him into who he is now, his memory was erased during the process as well. Now, he considers his life's mission to destroy anomalies, "Glitches" and AUs, seeing them as "mistakes". Error is somewhat demented and psychotic. He is determined to find all anomalies and "glitches" within various timelines and destroy them. His character is the one of confusion and somewhat hypocritical behaviour since he himself is an anomaly, but sees himself as the cleanser of timelines instead. He has been stated to be a complete mystery due to his erratic and unpredictable behaviours he has. He keeps "puppets" of his other alternate versions of selves that he talks to calling the standard Sans, called "Sans Classic" and naming the others by numbers. Despite admitting he is an anomaly/glitch, he says he is different and that he is the only one doing something about it. Error is a Black skeleton who wears black slippers and wears a black coat with a blue hood. His legs are red and has red/yellow fingers. He wears Black sweatpants that has a vertical blue stripe on each leg. His teeth are a light yellowish colour. The inside of his eyes are red as well as his nose. His right eye is a white pupil, while his left eye is blue with a thick yellow ring around it with a black pupil in the middle. there are blue markings on his face that assemble "tears". If Error blushes for any reason, like embarrassment, it is blue. In his AU, he is bent on destroying AUs which he considers 'glitches' or 'mistakes' in the multiverse. He is all black with a black hoodie, black pants with one blue stripe on each side, a red shirt, blue tear streaks down both his eye sockets, yellow teeth, black hands with red fingers and yellow tips. (he is sometimes portrayed to wear round red eyeglasses). He uses blue strings to tie up and shatter SOULS, if his strings go inside a victim, he can transfer his soul into the victim's body, making his body vanish and the victim's soul to vanish turning the victim into him. This makes him able to control the victim, while the victim is helpless. This is Error's "main weapon" because Error feels more comfortable with the strings, as Error doesn't have very good eyesight. Error has haphephobia which is mostly rooted in trust issues and is therefore very hesitant to get physically close to anyone. At random intervals, he can glitch up, filling his eye sockets with errors, giving him a major disadvantage if he's in battle. If Error had no strings, he would be a very easy problem to fix. Error also cannot see things far away clearly, as he uses round, red glasses a few times in the comic to show this. The glasses are kept in the pockets of his hoodie. He also knows how to knit. As shown in Underfail, he has love for cuteness, like Undercute. He wants to cuddle soft and fluffy creatures, despite his haphephobia. He refuses to destroy and erase cute things that shouldn't deserve it. His weakness is also that he likes chocolate. He is always freaked out by Guest due to him being a parasite. He can sometimes get distracted by "it". Error is even more horrified by Guest because Guest often gets too close to him due to having Haphephobia (not yet even considering the fact that Guest is a universe-wide-infecting parasite). Guest is a very hard opponent for Error because his soul lays in his left eye socket.