Kuwabara Kazuma is Yusuke's classmate and perhaps best friend. His power is his reiken, and he has but cannot control his sword that can cut through dimensions (like Itsuki's). He falls for Yukina, but he dislikes Hiei. Kuwabara is also one of the people that doesn't know that Hiei is Yukina's brother. He also has an older sister, Shizuru.