Gyōkaku Kumoi

Age has deeply lined Kumoi's face, framed by shoulder-length white hair, thick sideburns, and a broad white beard, and a smile reveals several teeth missing on his right side. For his public duties within the clan he favors a white kimono wrapped in purple that resembles a sweater, along with a pair of glasses. In private he sheds that image, slicking his hair back, trading the spectacles for a monocle over his left eye, and layering a red kimono over an ordinary Soul Reaper uniform.

The warm, benevolent manner Kumoi wears before others is a mask over a cunning and malicious core. Everyone takes him for a power-hungry schemer bent on stealing the clan headship from Rurichiyo Kasumiōji, and that ambition looks genuine enough, until it emerges that he has in truth been serving Shūsuke Amagai's designs all along.

As the steward overseeing Kasumiōji affairs, Kumoi seized on the death of Rurichiyo's father to make his move, quietly amassing supporters and raising a squad of assassins to murder any clan leader who opposed him or uncovered his aims. His central goal was to kill Rurichiyo herself, the last true heir, a task he repeatedly failed at within the Seireitei. He also perverted the clan's tradition of forging ceremonial blades to push his research into the Bakkōtō, ordering the weapons tested on living human subjects, many of whom were devoured on the spot. When Captain-Commander Yamamoto tried to intervene, the Central 46 barred him; Yamamoto's own pupil Shin'etsu Kisaragi went undercover to expose the swords, only to be captured, fitted with a Bakkōtō, and brainwashed into attacking his master, forcing Yamamoto to kill him and bury the truth.

During the conspiracy proper, Kumoi sends Hanza Nukui and a band of Bakkōtō-armed assassins to the Human World after Rurichiyo, installs the puppet Shū Kannogi as clan head, and keeps distributing the dangerous weapons despite their habit of consuming their wielders. As the Gotei 13 close in and storm the manor, he grabs Rurichiyo as a hostage, cuts down protesting officials, and prepares to end her life. Before he can, Amagai appears, strikes Kumoi down, harvests something from the Bakkōtō, and flees with Rurichiyo. Dying, Kumoi reveals with his final words that he had been Amagai's collaborator from the beginning.