Anzu

Anzu (formerly read as Zu) was a divine being, sometimes called a bird, sometimes a lion-headed eagle. He was given care of the entrance to Enlil's throne room and used this position to steal the Tablet of Destinies — the document on which all fates were written and which conferred supreme power on its holder. When Anzu flew away with it, all divine functions ceased. The young hero god Ninurta was sent to recover the Tablet and battled Anzu in an epic combat.

A monstrous bird of vast size with the head of a lion, wings spanning mountains, and eyes like the sun. His cry was like thunder. He nested in the mountains. When he flew, he created storms.

By possessing the Tablet of Destinies he could negate any weapon directed at him (arrows turned back in midair). Created storms through his flight. Divine in origin and so immune to ordinary harm.