Ryuuzaki

Ryuzaki is the runner-up in the Japanese Duel Monsters tournament. He is good friends with the champion Insector Haga, and tends to use cards related to dinosaurs (thus his nickname "Dinosaur") due to his love of dinosaurs. In the English anime, he is named after the tyrannosaurus rex and the Raptor, two types of dinosaurs. (Source: Wkipedia)