Origin story

In entertainment, an origin story is an account or backstory revealing how a character or group of people become a protagonist or antagonist.

In American comic books, it also refers to how characters gained their superpowers and/or the circumstances under which they became superheroes or supervillains. In order to keep their characters current, comic book companies, as well as cartoon companies, game companies, children's show companies, and toy companies, frequently rewrite the origins of their oldest characters. This goes from adding details that do not contradict earlier facts to a totally new origin which makes it seem that it is an altogether different character.

A pourquoi story, also dubbed an "origin story", is also used in mythology, referring to narratives of how a world began, how creatures and plants came into existence, and why certain things in the cosmos have certain yet distinct qualities.