Atem Yugi, also known as Yami Yugi, is the spirit of an ancient Egyptian Pharaoh who resides within the Millennium Puzzle and shares a body with Yugi Mutou, the protagonist of Yu-Gi-Oh!. As Yugi's darker, more confident alter ego, Atem takes over during duels and critical moments, helping his friends overcome dangerous opponents. Throughout the series, Atem seeks to regain his lost memories and ultimately find peace. His presence provides guidance, strength, and protection to Yugi and his friends.