His true name is Sugoroku Moto but everyone just calls him "Grandpa". He is a very good duelist and taught Yugi and Joey about the heart of the cards. Little of him is seen through the series but his deck is used by his grandson Yugi. I think he is Yugi's only living relative. Grandpa also had the fourth blue eyes white dragon that exists in the world, but Seto Kaiba defeated Grandpa in a duel and tore the card in two.