Archangel Metatron, the "Right hand" or "Messenger" or God. Originally a human man named Enoch, but he and his brother Elijah were such good faithful men that they were turned into angels, though Metatron is significantly more powerful. He also, according to the Gnostic Christian mythos created Sacred Alchemy.
I'm an angel buff :3 Going off the Gnostic lore, coming from "The Book of Enoch" and other texts taken out in the councils of Nicea and Trent.
Sorry for the wall of texts. If there's such thing as an angel otaku... XP I'm guilty