Yami Bakura is the evil spirit of the Millennium Ring. He appears as a reoccurring secondary antagonist for most the series, until the final arc where he's the main and final antagonist. Through the Millennium Ring, Bakura Ryou became host to the spirit, allowing him to possess Bakura; even able to mimic his host's personality almost perfectly that he's able to fool Bakura's friends. Yami Bakura is the longest running and most prominent adversary in the entire series, being an antagonistic counterpart and a great adversary to Yami Yugi.