This is an interesting one

Error and Trichloromethane where once good friends, inseparable, people used to say. They did everything together. Video games, school classes etc. However one day, Error saw Trichloromethane's sister trying to murder someone, so Error killed her before she could kill that person. Error realized that he killed her (he was only trying to stun her), so he ran away. Trichloromethane got the horrible news only hours later. Trichloromethane locked himself in his room, in disbelief his little sister was dead. After a month of introversion, he came out of his room and ran to the sacrifical temple that most of the townspeople came to to worship the Collector. He asked for one thing: revenge for his sister. However, Mr. Void answered instead of the Collector.

Mr. Void put a hex on Error, and any time he wanted to help someone, he would feel tremendous pain in his body and collapse. Mr. Void also put a hex on Trichloromethane that made him a glitching demon. Trichloromethane had no more control of his body anymore, and Trichloromethane, or the husk that was him, hunts down Error. All Trichloromethane wanted was pain for Error, not for Trichloromethane himself to never feel the sweet embrace of death and share a body with a demon. If only the Collector answered...