Marik was a villain who also planned to take over the world, with children’s trading cards. Oh, creepy. He had two different selves and a millennium rod that gave him great power.
Marik was one of the highest skilled duelists in the series being able to defeat quite a few major characters including Bakura and Mai Valentine along with sealing both of them into the shadow realm with his millennium item. He had a millennium rod, one of seven millennium items with abilities. He also seemed to suffer from multiple personality disorder with both a dark side and a less dark side, which made him even more creepy.