Yami Yugi is the 3,000-year-old spirit of Pharaoh Atem sealed within the Millennium Puzzle. After Yugi Muto solves the puzzle, Atem inhabits his body as an amnesiac, protective spirit who takes over during dangerous games. He is a master duelist who acts as a stern, righteous judge in early stories before evolving into a caring mentor to Yugi and his friends.