"Reticent and keeps a low profile, but he keeps his love for his friends and a lot of fighting potential on the inside. The Hana-Gumi can always count on him."
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.