Spirit Keys

Along with the spirit gate, Kagemaru created these as a means to get high-level duelists to duel each other in order to generate the duel energy necessary to revive the Sacred Beasts. Kagemaru says himself that they were in fact unnecessary to open the gate. Sheppard gave one key to the seven top duelists in the academy: Chazz, Bastion, Jaden, Alexis, Crowler, Zane, and Banner.