Sojiro Kusaka

As a student, Kusaka is friendly, diligent and strongly competitive with Hitsugaya. Their rivalry develops alongside genuine affection: they train together, and Kusaka is one of the few people with whom the reserved Hitsugaya forms a close early bond.

His execution transforms that ambition into bitterness. Kusaka becomes convinced that Hyōrinmaru was unjustly taken from him and that Soul Society’s leaders must pay for erasing his life. Although his grievance originates in real institutional cruelty, revenge grows into entitlement and megalomania. He dismisses Hitsugaya’s attempts to reason with him and insists that only one of them can possess the sword.

Kusaka is a proficient swordsman with substantial spiritual power. His Zanpakutō is another manifestation of Hyōrinmaru, granting him ice abilities closely resembling Hitsugaya’s. Its Shikai produces an ice dragon and allows Kusaka to freeze targets or reshape the surrounding battlefield.

The Ōin greatly expands his capabilities. Kusaka uses it to teleport, distort space and restore his physical form. Once its seal is broken, its energy transforms him into an enormous ice-covered creature with increased strength, durability and destructive power. This state is unstable and dependent on the artifact.

Contrary to some summaries, Kusaka is not repeatedly and decisively beaten by a weakened Hitsugaya. Their encounters are contested, and Kusaka’s borrowed power frequently lets him injure or overpower his former friend. His final defeat requires combined opposition.

At the Shin’ō Academy, Kusaka and Hitsugaya discover that both have awakened Hyōrinmaru. Central 46 refuses to recognize two wielders of the same Zanpakutō and orders them to fight. Hitsugaya is willing to surrender his claim, but Kusaka attacks first, hoping to prove himself through victory.

After Hitsugaya defeats him, Central 46 awards Hyōrinmaru to Hitsugaya and secretly orders the Onmitsukidō to execute Kusaka. His records are erased, leaving Hitsugaya burdened by guilt and forbidden from discussing what happened.

The Ōin later reconstructs Kusaka’s body. He attacks the convoy transporting it, wounds Shunsui Kyōraku with Hyōrinmaru and creates evidence implicating Hitsugaya. With the artifact secured, Kusaka begins his campaign against Soul Society.

Kusaka ultimately breaks the Ōin’s seal and assumes a monstrous ice form. Hitsugaya and Ichigo defeat him together, and Kusaka dissolves as the artificial dimension generated by the artifact collapses.

Tōshirō Hitsugaya is Kusaka’s former friend, academy rival and fellow wielder of Hyōrinmaru. Their relationship is destroyed by Central 46’s decree, although Hitsugaya continues to regret Kusaka’s fate.

Ichigo Kurosaki opposes Kusaka’s attack on Soul Society and joins Tōshirō Hitsugaya in the final battle.

Shunsui Kyōraku is wounded as part of Kusaka’s attempt to frame Hitsugaya. Yin and Yang serve Kusaka as loyal Arrancar subordinates during his rebellion.