He participated in his generation's Freshmen War, but was defeated by Hisashi Amachi. However, even after the match was called, Amachi continued to attack an already-downed Ozaki, breaking his rib and arm . After this loss, he was recruited by Mutou Renji to form the Hana-Gumi.
As a member and officer of the Hana-Gumi, Ozaki served as the group's tactician and works alongside Renji to gather important data.
- Ozaki vs. Amachi - Lost