Sugoroku Mutou is Yugi Mutou's grandfather, the family resemblence is quite obvious with the hair style. He owns a game shop where he and Yugi live. That is how Yugi is loaded with the newest games.

Many years ago he traveled to America where he made some friends and enemies. That is where it is believed he won the uncomplete Millenium Puzzle in a game. Sugoroku gave his grandson the Millenium Puzzle because he hoped it would help him become stronger and make friends.

He cares greatly for his grandson and is aware of his other side. He is the reason Yugi ventured to Pegasus's Duelist Kingdom. Pegasus trapped his soul onto a video cassette. And the reason for Kaiba's rivalry with Yugi. Kaiba stole his prized card, the Blue Eyes White Dragon and Yugi defeated him to win it back.