Juudai is your regular Duelist, who loves to play the game. He's a member of the Slifer Red dorm and is usually called a Slifer Slacker. He wants to become the next "King Of Games" and is willing to duel anyone for the title.
Juudai has the ability to see Duel Monster spirits. His spirit partner is Winged Kuribou. In the anime, Juudai received Winged Kuribou from Yugi Moto while in the manga he received it from Kouyou Hibiki.
In the anime, Juudai first plays an "Elemental Hero" deck, then a "Neo-Spacian" deck but now he plays a deck combined with "Elemental Heroes" and "Neo-Spacians." His strategy is based on fusing monsters together. In the manga, he plays an "Elemental Hero" deck, however it differs from the deck in the anime.