Duke Devlin, known as Ryuji Otogi (御お伽とぎ 龍りゅう児じ Otogi Ryūji) in the manga and Japanese version, is the creator of the game Dungeon Dice Monsters. Duke also owns the "Black Clown" game shop, which rivals Solomon Muto's Kame Game. In the manga, the Black Clown is owned by his father, "Mr. Clown."
