Rukia and Kaien, the Sorrowful Reunion

While Sado weathers Gantenbainne's heavy blows and proves he still has fight left, Rukia stands frozen before a smiling man claiming to be Kaien Shiba, the mentor she killed years earlier. His warmth and blunt manner feel achingly genuine, and he even recreates the Thirteenth Division training yard to spar with her, reliving their old lessons.

He recounts how Metastacia, engineered by Aizen to reform in Hueco Mundo, had merged with Kaien and taken his shape, only for Kaien's iron will to seize the resulting body. Then he abruptly turns his blade on Rukia, opening a cut on her cheek. Elsewhere, Gin Ichimaru toys with the shifting corridors of Las Noches as Ulquiorra looks on with suspicion.

The false Kaien presses Rukia to atone for his death, then twists the request into a demand that she bring him the severed heads of her friends. His mockery of the real Kaien's memory finally hardens her resolve; she denounces him as a fraud, recalling how the true Kaien spoke gently even as his lungs filled with blood, and releases Sode no Shirayuki. Their fierce exchange shows him effortlessly slipping past her ice dances, hinting that he is far more than he appears.

Rukia is confronted by an enemy wearing Kaien Shiba's face and memories, who spars with her and recounts his resurrection in Hueco Mundo. After he demands she murder her friends as atonement, Rukia rejects him as an impostor who dishonors Kaien and releases her Shikai. The ensuing clash reveals that he can easily evade her signature ice techniques.

Episode 154 adapts the latter part of chapter 263 and chapter 264. The Shinigami Illustrated Picture Book skit has Renji puzzling over interim captains as Kira and Hisagi celebrate their newly granted authority. The anime expanded flashbacks to Kaien and Metastacia and lengthened the wooden-sword sparring between Rukia and the disguised Aaroniero.