Crevan

Crevan was a human mage. He had alligned himself with Malygos during the Nexus War, and was therefore placed inside the Violet Hold by the Kirin Tor. The Kirin Tor told Crevan's family that he had died in battle. Later he tricked his nephew, Aodhan, to open his cell and locate a book inside Dalaran's library, a book that could return the powers, that the Kirin Tor has removed, back to him. He later used the book to open the other cells of the Violet Hold. Finally he attempted to make Dalaran drop from the sky, but he was stopped by Aodhan, Rhonin and Simeon.