I remember this idea brought to the logical extreme (though I don't remember author's name).

A character gets born, lives, dies, repeatedly, in different circumstances. At one.moment he manages to remember something that a being from outside time tells him between incarnations, in "limbo" / "bardo" type of setting.

All the people in the world is that same character, only transpoted in time. All the worst villains he faces are himself, all the best saints he meets are his (future) selves. This world is entirely by him.