Yuugi Mutou is the main character and protagonist of the original Yu-Gi-Oh! series, along with the spirit of Yami Yugi. Yuugi is kind-hearted and child-like. He is good at games, riddles, and puzzles, especially Duel Monsters. It was stated once that Yuugi is the modern day version of Pharaoh Atem.
Together with the spirit of Pharaoh Atem, he holds the title "King of Duelists".
Yuugi possesses the three thousand-year-old mystical Millennium Puzzle, which allows his body to bear host to the spirit/soul of the Puzzle, Yami Yugi.
He lives with his paternal grandfather, Sugoroku Mutou, and his mother. In the manga, Yuugi's father (Sugoroku's son) is living away from his family on business.
Yuugi is part of a close-knit group of best friends: Katsuya Jounouchi, Honda Hiroto, and Mazaki Anzu as well as Bakura Ryou. Miho Nosaka is also one of Yuugi's friends in the first series anime. Yuugi's friends often cheer him on from the sidelines, and Katsuya has dueled at his side. Yuugi has been friends with Anzu since childhood and has a romantic crush on her. Anzu has been shown to have romantic feelings for both Yuugi and Yami Yugi.