Yami Bakura

Yami Bakura, known as Dark Bakura (闇やみ獏ばく良ら(バクラ) Yami Bakura) in the Japanese version, is the evil spirit of the Millennium Ring. He appears as a recurring secondary antagonist for most of the series, until the final arc where he is the main antagonist. Through the Millennium Ring, Bakura Ryou became host to the spirit, allowing him to possess Bakura.