Asmodeus

Asmodeus (pronounced as-MO-day-us) is the most powerful of the nine archdevils that inhabit Hell, and the only one of Hell's rulers to claim full divinity. It was he who is credited with the penning the contract of creation, within which his followers believe is hidden the means for their patron's eventual rise to supremacy.
History
According to the Book of the Damned, Asmodeus is one of the two primeval entities with his brother and equal Ihys.