Ichigo Rages! The Assassin's Secret

Amagai vanishes with Rurichiyo using an unfamiliar Kidō that hides his Reiatsu, leaving Ichigo furious until a Jigokuchō gives them a trail. Reaching Yamamoto's office, Amagai names Shin'etsu Kisaragi and moves to kill the Captain-Commander, but the bodyguards Kenryū and Enryū intervene, binding him with Benishidare and Daichimaru while freeing the princess. Amagai breaks loose, snatches the Bakkōtō from Yamamoto's desk, and feeds its nucleus to his own weapon, awakening a new form coiled around his arm.

Yamamoto releases Ryūjin Jakka and floods the room with fire, but Amagai stabs his Bakkōtō into the ground and the flames die, revealing that his blade negates every Shinigami's powers except his own Raika. He activates Bankai and hurls a wave of fire that blows out the wall. When he turns his threat on Rurichiyo and her guards, Yamamoto insists he is the only target, only for Amagai to declare he means to destroy the Kasumiōji heir alongside the Captain-Commander. Ichigo crashes in, apologizes to the princess, and demands to know who Amagai truly is.

Over at the Kasumiōji compound, the captains and Yoruichi piece together the plot: Gyōkaku Kumoi first forged the Bakkōtō from royal sword-craft, and Amagai used them to climb into the Gotei 13 for his own ends, with Ichigo's interference forcing his hand early. Amagai then reveals the core of his grief. Yamamoto slew his father, Shin'etsu, who had gone to investigate the Bakkōtō, and Amagai spent years changing his identity, training under the Kasumiōji, and rising through the Patrol Corps to avenge him. He sends fire at Yamamoto, but Ichigo bats it aside, blasting Amagai for dragging innocents into his revenge and squaring up to move him by force.

Amagai is confirmed as the mastermind. He empowers his personal Bakkōtō, which nullifies all Shinigami abilities but his own, and unleashes his Bankai against Yamamoto. Yoruichi and the captains uncover the Bakkōtō's origin under Gyōkaku Kumoi. Amagai reveals Yamamoto killed his father, Shin'etsu Kisaragi, framing his entire infiltration as revenge. Ichigo intervenes and challenges Amagai directly.

An anime-original episode, the 187th of the series, set in the New Captain Shūsuke Amagai arc with no adapted chapters. Its Shinigami Illustrated Picture Book corner has Chōjirō Sasakibe, inspired by English gentlemen he once observed, grow his own tea leaves and cause an explosion in the First Division quarters while brewing.