Beginning of the Death of Tomorrow

Standing over a bleeding Ichigo Kurosaki, Yoruichi Shihōin orders him up as his materialized sword spirit, a spined version of Zangetsu, threatens to haul him to his feet. Rewinding half an hour, Yoruichi presents the Tenshintai, a stealth-corps tool that forcibly drags a Zanpakutō Spirit into the physical world. Achieving Bankai, she explains, means summoning that spirit outward and beating it into submission, a feat that normally takes a decade, but she believes his clash with Kenpachi Zaraki has readied him. Piercing the Tenshintai with his blade will trigger the manifestation, which she can sustain for only three days.

Ichigo drives Zangetsu into the tool without asking what failure costs, and the spirit appears, scattering dozens of identical blades across the ground. Only one is the true Zangetsu, and Ichigo must find and seize it to defeat the spirit before it kills him. The two grab separate swords and clash as Yoruichi watches. Elsewhere, Renji Abarai breaks out of his cell, Momo Hinamori tucks Aizen's letter away with grim purpose, and a shattered Izuru Kira, wracked by guilt for crossing blades with Hinamori, is approached by his captain, Gin Ichimaru, who offers to take him along.

Yoruichi reveals the Tenshintai and its role in her three-day method for reaching Bankai. Ichigo externalizes Zangetsu and begins the trial of finding the one true blade among many. Renji escapes his cell, Hinamori resolves to act on Aizen's letter, and Gin recruits the guilt-ridden Izuru.

The chapter, which lends its name to the fifteenth volume, sits in the Soul Society arc and was adapted into Episode 45, Overcome Your Limits. It launches Ichigo's Bankai training in earnest while advancing the parallel intrigue surrounding Aizen's death and Gin's movements.