Raven Blood Raven was a corrupted rogue boss found in Act One of Diablo II. The game's lore said that she was the Rogue, the character from Diablo I, returned to her Monastery and corrupted by the powers that the Dark Wanderer unleashed upon it, summoning forth Andariel.
It is not known if Blood Rave she will return in Diablo III; Blizzard has given no indication that she, or any of the other Sisters of the Sightless Eye, will.