Monotheism is a religious belief advocated by some Star Elves, Asguardian Dwarfs, and aliens that states that the Creator God is the one true God.  Religious differences between monotheists and the supporters of Incarnatism have colored politics within the Star Imperium and later the United Planets.

Many monotheists acknowledge the existence of angels who serve the Creator and demons who oppose him, although angels and demons are definitely not considered true deities.