Turn Back The Pendulum 4

In his cell, Mayuri Kurotsuchi trades insults with Hiyori before congratulating Urahara and declining the offer to leave, claiming contentment. When Urahara points out there is nothing to tinker with in the detention pit, Mayuri asks his real motive. Urahara reveals his plan to found a Research and Development Institute within the Twelfth Division and wants Mayuri as its vice-president, adding that should he die, the whole organization would pass to Mayuri to run as he pleases. Amused, Mayuri accepts, calling Urahara a thoroughly unpleasant man.

At the Kuchiki manor, a young Byakuya drills his swordsmanship when his grandfather Ginrei announces a visitor. Yoruichi appears, and Byakuya lashes out at her as a demon cat before she snatches his hair tie with Shunpo and taunts that he will never catch her. As Byakuya gives chase with his own supposedly superior Shunpo, Ginrei muses that the boy would improve greatly if he could master his temper. Elsewhere, Kaien Shiba again turns down Ukitake's offer to become his lieutenant, insisting others deserve it more. Disappointed, Ukitake speaks of a prodigy who finished the Shin'ō Academy in a single year, the same age as Byakuya, and now serves in the Fifth Division. That prodigy, Gin Ichimaru, is praised by Aizen for killing the division's Third Seat, which Gin dismisses as no loss.

Mayuri agrees to help launch the Shinigami Research and Development Institute, formalizing his place under Urahara. Vignettes flesh out the wider cast of the era, showing a young, hot-tempered Byakuya sparring against Yoruichi and Ukitake's fruitless pursuit of Kaien Shiba as lieutenant. The chapter's darkest note introduces Gin Ichimaru as a child prodigy already killing on command, and Aizen's approval quietly signals the corruption taking root within the Fifth Division.

This fourth chapter of the Turn Back The Pendulum flashback was adapted as part of Episode 208, Aizen and the Genius Boy. It marks the formal creation of the research institute and the first glimpse of the young Gin Ichimaru under Aizen's influence.