As of Mists of Pandaria, Ras Frostwhisper has been removed from the game.
Ras Frostwhisper was once a human mage from Stromgarde. He was a hedge mage, a rogue wizard that never received his formal training from Dalaran. He was among the first to join the Cult of the Damned and quickly advanced through its ranks. He turned himself over to the Lich King when the Scourge invaded, in return for immortality. Upon the ground in Stratholme, within the Slaughterhouse, Ras Frostwhisper took a dagger to his own neck and cut from one side to the other—all the time with a smile upon his face. His corpse fell onto Menethil's Gift and it is there that the Lich King raised his fallen corpse as a Lich, granting him immortality while Leonid Barthalomew the Revered looked on. He spent his time overseeing the operations in the necromancy school of Scholomance. Magistrate Marduke has a plan to rob the lich of his powers, return him to his mortal form, and slay him once and for all. He had an ogre servant Kormok.
After the Cataclysm a new quest from Alexi Barov to kill him once more was added. During the liberation of Stratholme Eligor Dawnbringer commented that Ras still haunts Scholomance, though he should already be killed at this point. The fact that he doesn't appear in the updated instance indicates that he is killed. Eligor's text would then be considered an error.