Zangetsu Becomes an Enemy

Within the Seireitei, a handful of freed blades loiter and bicker while their leader fixes his attention on Ichigo Kurosaki. Muramasa explains that each sword spirit is a soul born inside a Shinigami, drawing on the same power as its master yet holding a will entirely its own, and declares that his purpose is to sever those spirits from the ones who wield them. He confesses that Rukia was merely a lure used to draw Ichigo into place, then baits him into combat. After the two trade strikes across the rooftops, Muramasa distorts the space around Ichigo, pins him flat, and plunges a hand into his chest to tear the spirit dwelling there into the open.

What answers the summons is not the partner Ichigo expects but a hostile double, blade in hand, that charges without a word. As the exchange escalates, gashes seal over through High-Speed Regeneration and Ichigo's inner Hollow claws its way to the surface, wrapping him in a mask, reshaping him into a feral shape, and firing a Cero. At the Fourth Division, meanwhile, Unohana and Isane learn from Nemu that Mayuri tested the split on his own body and confirmed the spirits are now wholly separate beings, raising the grim chance that a defeated spirit could be lost forever. Refusing to hand his strength to the Hollow, Ichigo rips the mask apart, sheds the transformation, and drops unconscious as a baffled Muramasa wonders exactly who he just faced.

Muramasa lays bare the nature of Zanpakutō spirits and admits he steered Rukia the whole way to reach Ichigo. He drives Ichigo down, opens a churning portal beneath him, and pulls the spirit out by name. The manifested Zangetsu turns on Ichigo and overwhelms him until his inner Hollow hijacks his body. In a parallel thread, Nemu reveals Mayuri experimented on himself and Unohana agrees to endure his invasive examination in return for immediate findings. The battle closes when Ichigo cracks the Hollow mask through sheer will and collapses, no longer recognizable to the sword spirit that broke him free.

This installment sits inside the anime-original Zanpakutō Unknown Tales arc and adapts no manga chapter. It premiered in Japan on August 18, 2009, and aired in English on December 4, 2011, bracketed by the opening Shōjo S and the ending Mad Surfer. Powers shown across the fight include Getsuga Tenshō, Muramasa's illusions, spirit manifestation, Shunpo, High-Speed Regeneration, and a Cero, with Benihime and Tensa Zangetsu surfacing only in flashback. The comedic Shinigami Illustrated Picture Book segment trails Iba, Hisagi, and Izuru as they grind through stacks of forms for a beach outing, only for the weather to spoil the whole trip.