Swords of Origin

Nimaiya names the faceless figures swarming Ichigo and Renji as Asauchi, blank Zanpakutō able to become anything. He describes how these nameless swords are handed to trainees at the Shin'ō Academy and formally granted upon graduation, then shaped over years of shared life into a Shinigami's personal blade. Because he forges every Asauchi himself, he insists the swords are enraged by how carelessly the two treat their weapons, and he proposes a test of whether the Shinigami or the Zanpakutō is truly superior.

Elsewhere, deep in the Muken level of the underground prison, Kenpachi Zaraki steps out of an elevator to face Retsu Unohana, marveling that she secured such a vast, sealed arena for their fight. She explains that only a place this isolated suits his unrestrained swordsmanship and that Captain-Commander Shunsui Kyōraku sanctioned it. Turning to face him with her hair loose and a chilling grin, she remarks that he would fit right in as a powerless criminal.

Kenpachi retorts that both of them would be nothing but criminals without their strength, and each acknowledges the aching scar the other once gave them before charging. Far above, Shunsui recalls that Yachiru Unohana belonged to the original, strongest generation of captains who founded the Eleventh Division. Once the most feared outlaw in the history of Soul Society before Yamamoto recruited her, she took a name meaning "Eight Thousand Styles" for her mastery of countless sword forms, and Shunsui admits that only one of the two combatants will walk away alive.

Nimaiya explains the nature of the Asauchi and sets Ichigo and Renji against them. In Muken, Retsu Unohana reveals her savage side and confronts Kenpachi Zaraki. Shunsui Kyōraku recounts Unohana's history as the founding, most notorious Kenpachi of the Eleventh Division. Both fighters acknowledge their shared scars and begin a duel only one can survive.

The chapter lays out the lore of the Asauchi and Zanpakutō creation while opening the pivotal Unohana versus Kenpachi confrontation of the Thousand-Year Blood War arc. It also confirms Unohana as the original bearer of the Kenpachi title. The events were adapted in Episode 375, "THE DROP."