Deicide 9

Arriving in the Dangai, Aizen finds the place nostalgic and refuses to step aside as the Kototsu bears down. Ignoring Gin's caution that the cleaner is a creature of reason best left undisturbed, Aizen lets it slam into him; it bursts apart while he stands satisfied and unharmed. He muses that reason exists only for those who cannot live without clinging to it, then invites Gin onward to the edge of reason as they leave the Precipice World.

Back in Fake Karakura Town, Isshin headbutts Ichigo and insists they head to Soul Society to guard the town. Ichigo calls it hopeless, arguing that no one can defeat a monster wielding such Reiatsu, and Isshin realizes his son does not truly grasp the nature of that power. When Isshin begins walking and asks if Ichigo will just sit and weep, the boy's resolve returns and he tells his father to open the Senkai Gate.

Aizen and Gin step out of their own gate slightly off course, trading light banter about the miscalculation. Meanwhile, Isshin halts Ichigo in the Dangai and notes that Aizen destroyed the Kototsu, a feat Shinigami should be incapable of. He explains that the Precipice World is a separate dimension where time flows far more slowly than in either the Human World or Soul Society, making its sluggish pace ideal for training. Asked what he will teach, Isshin answers simply: the Final Getsuga Tensho. The two villains reach the real Karakura Town just as Keigo Asano stirs awake.

Aizen proves his new power by shrugging off and destroying the Kototsu inside the Dangai. Isshin rallies a despairing Ichigo, then chooses the Precipice World's slowed time as the setting to teach him the Final Getsuga Tensho.

The 407th chapter continues the Deicide arc in the forty-seventh volume, END OF THE CHRYSALIS AGE. It introduces Isshin's training plan and was adapted into anime Episode 301, Ichigo Loses His Fighting Spirit!? Gin's Expectation!