Pazuzu

Here's my take on Pazuzu (or Pazuza, or Fazuzu...), the king of east wind demons in Mesopotamian mythology, son of the god of evil Hanbi/Hanpa, and brother of the monstrous giant Humbaba. He is an ambiguous figure, who has incubus-like demons called lilu at his service, but he also acts as a protective "genie" against the demoness Lamashtu, who represents the southwest wind that brings famine and locusts, and threatens pregnant women, kind of like a proto-Lilith.

Pazuzu was made famous by "The Exorcist" (1973), where he is represented more as a purely evil christian demon, even though his cult predates the birth of Jesus Christ.