Suddenly appearing in front of Minato Tribe, Kazuki is a mysterious young man who offered to join the tribe.

Since his left hand is injured, he doesn't seem to be able to play XB properly. However, for some reason, he has tactics in XB and has details on how to handle beam bats, bringing Minato victory with his wisdom.

Kazuki actually trained with Ojiro to become the ultimate XB player but after he got defeated; Ojiro broke his hand so that he cannot play XB in the future again. He joined Minato Tribe to get revenge against Chiyoda Tribe.