User:SI! Sans

Illness used to be human, a horrid man by the same of Samuel, Sam in short, who committed crime regularly, Crimes so horrid he was seen as a monster, or the most depraved human alive. Eventually, his life was taken in a car accident.

After which, a being of immense power beyond human and non-human understanding Known as Unum Supra makes a deal with him, offers him the job of torturing others that are equally or way worse than him via a game, he accepts, with the unexpected condition of being a twisted version of the Undertale character known as Sans.

eventually over time, the souls of the condemned ones start filling him with more joy, he became more dangerous, more aggressive with the victims and starts hunting people that aren't even guilty of their sins. but he doesn't care.. he wants more... power

Information via https://undertale-exe-and-creepypasta.fandom.com/wiki/Sansational_Illness.dat