Zorc is a huge, evil monster whose origins are unknown. So far, he has only appeared in Yami Bakura's spin-off show, Zorc and Pals. He apparently has a terminal disease of some sort. He is also a member of Marik's Evil Council. He has reportedly destroyed the world many times.
In an episode of Zorc and Pals we find out that Zorc's mother wanted him to be a lawyer and that he is married to Marik Ishtar.
It is also revealed in episode 46 that after the cancelation of Zorc and Pals, Zorc got a part in another spin-off show, the Suite Life of: Zorc and Cody