Haziael, The Lost Angel, is a Unique Angel found in the Realm of the Banished in Act V of Diablo III.
He is hostile to the player, and, strangely, not hostile towards the other monsters (including demons) in the area. Haziael's wings, just like the wings Erelus, are black in color, apparently a result of long separation from the Crystal Arch.
In combat, he has Reflects Damage, Fast, and Electrified affixes.