Doushi

The Master is the leader of the Temple (an organization within the Junior Duelist Center), but very little is known about him. Throughout the first season he appears in a long black, hooded robe with his face half concealed by his long blond hair. The Master is Hakuoh's teacher and dueling coach. Knight suggests that the Master has only taken an interest in Hakuoh because he plans to use the young duelist in obtaining his "revenge" against the creature world. The Master seems to be responsible for Hakuoh's brainwashing and pushes Hakuoh to attack Shobu with Alcadeias, Lord of Spirits, even after Hakuoh's defeat. After Hakuoh's defeat in Season 1, the Master has not been seen since. (Source: Duel Masters Wiki)