Sōjirō Kusaka

Kusaka stands tall with long black hair gathered into a bun and a curtain of bangs veiling his right cheek and eye. A prominent scar runs down that same side, a relic of his execution, and his once-violet eyes burn red after his return to life. To hide who he is he wraps himself in a pale brown cape echoing Hitsugaya's own and dons a mask resembling a Hollow's.

In his early days Kusaka was an idealist devoted to upholding Soul Society, a friendly rival who pushed himself against Hitsugaya in their studies. The forced duel that followed and his summary execution shattered that idealism. When he resurfaces he is embittered and consumed by a desire to punish Soul Society for the rigid, merciless laws that condemned him.

As students Kusaka and Hitsugaya each encountered the same ice spirit, Hyōrinmaru, and their bond deepened over that shared gift, until Central 46 ruled that no two Shinigami may wield one Zanpakutō and ordered them to duel for the right to keep it. Kusaka struck first, but the council awarded the blade to Hitsugaya and had Kusaka executed on the spot, a covert killing whose records were then erased. The royal artifact known as the Ōin later restored him to life, and Hueco Mundo nurtured him into a new existence, complete with two Arrancar servants who command fire and lightning.

Bent on revenge, he returns cloaked and masked, framing Hitsugaya for an assault and drawing Soul Society into branding his old friend a traitor. His plan centers on the Ōin, which he means to use to crown himself king; when Hitsugaya refuses to cut the seal, Kusaka slices it himself and swells into a colossal purple ice dragon, effectively a god able to regenerate from any wound, spawn Hollows, and raise a castle within an expanding pocket world. It takes the combined efforts of Ichigo Kurosaki and Hitsugaya to bring him down, and in his final moments he shares one last clash with Hitsugaya, who assures him their friendship will endure as Kusaka fades away. His version of Hyōrinmaru mirrors Hitsugaya's, loosing a dragon of ice from every slash that freezes whatever it touches.