Gods.
In every world that is capable of giving birth to a sentient and intelligent life, there will always exist a god. Or rather, gods.
An older god, which determines the fate of the world, and a younger one which would be born from that world. Either can play the role of good and evil, but both play the part of chaos.
An older god could choose not to take action and just let the fate of the world weaved itself. The younger one, however, would always be the center part of that world's history. Be it in the form of a messiah, or in the form of the devil.
An older god would know that he is a god, but the younger one would not, at least not at the very end of his life.
"Demon God Xanthus was supposed to go to the Planet of the Gods, but he chose eternal death. Such a shame really, he would have been a great god that would have surpassed me. The young gods, you see. We treat them like our children."
