Kaiba duels against the mysterious eighth duelist who is soon revealed to be Ishizu, and she, in turn, is revealed to be Marik's elder sister. She plans to take Obelisk the Tormentor back and save her brother from himself, as her necklace shows her, and plants a trap in the midst of Kaiba's arrogance. While trying to call out to his sister, Marik is banished from his own body by the evil force controlling him.
Yu-Gi-Oh! Greek Forum