From Halopedia, the Halo wiki
|There is more information available on this subject at John Kassir on the English Wikipedia.|
John Kassir (born October 24, 1957) is an American actor and voice artist, best known for his role as the Crypt-Keeper in Tales from the Crypt.
He may have been brought in by his then-wife, Julie Benz, to help in the production of Halo 2. He was one of the extra voice talents, voicing a few of the Marines throughout the game.