Yami Yuugi, also known as the 'Dark Yuugi,' is a mysterious spirit inhabiting the Millennium Puzzle in the anime series Yuugiou (Yu-Gi-Oh!). He shares a body with the main protagonist, Yuugi Mutou, emerging during times of crisis or duels. Yami Yuugi is confident, strategic, and fiercely protective of his friends. He plays a crucial role in the series by helping Yuugi and his companions overcome dangerous foes, often through high-stakes games and duels.