Asmodeus

Asmodeus is the evil god of tyranny, domination and sin. He is the King of Hell, ruling the Nine Hells of Baator, the Duke of the Ninth, Nessus, and father of Glasya, Duke of the Sixth Hell, Malbolge.

Asmodeus, archangel and exarch of He Who Was, betrayed his god and killed him, but not before He Who Was cursed Asmodeus and his follows, transforming them into the first devils and the astral dominion of Baathion into Baator, as a prison for them. Over the coming millennia, Asmodeus worked to erase all knowledge of He Who Was from existence, including his name, out of fear of the god returning. Asmodeus offered his aid to the gods in their war against the primordials in exchange for ascending him to the pantheon.