The devil within

Denki and bakugo became fast friends for years until bakugo moved to America to become a professor at the age of 13. At the age of 15 bakugo goes to Prue to help a fellow professor of his on a job he's doing. When he gets there he learns that the fellow professor was possed by a demon, not a typical demon that's told of in the Bible but a demon that can look like anything from short and fat with claws to long and skinny with multiple human faces it uses to speak. The professor explains all his finding to bakugo and what it means. When the demon in the professors body goes to attack bakugo the professors heart wins for just a moment for him to light his body on fire killing the demon because he says he doesn't want to live as a demon that he couldn't win against it and couldn't fight against it anymore. Bakugo, with all this new information, continued to explore the world of the demons with caution until he couldn't go any father on his own.