Ichigo Kurosaki vs. Shūsuke Amagai

is a battle that takes place in Seireitei and is the final event of the Kasumiōji Conspiracy.

Prologue
After killing Gyōkaku Kumoi and taking Rurichiyo Kasumiōji captive, Shūsuke Amagai disappears with the the captive princess. Rukia Kuchiki informs Ichigo Kurosaki that she has never seen a spell like Amagai just used and Ichigo becomes angry, fearing for Rurichiyo. At the First Division Barracks, Amagai confronts Genryūsai Shigekuni Yamamoto. Yamamoto asks what Amagai wants and why he has Rurichiyo. When Yamamoto expresses that he does not know the answer to his question, Amagai questions if Yamamoto never thought there might be people who would murder him if they had the chance. Yamamoto questions why he would want to murder him and Amagai responds by simply saying Shin'etsu Kisaragi. He has come in his name to kill Yamamoto. Amagai grabs his Zanpakutō but is interrupted by Ryūsei Kenzaki who uses his Benishidare to create a blinding mist in the air before attacking Amagai and having Rurichiyo escape. As Amagai tries to counter, Rusaburō Enkōgawa releases his Zanpakutō and covers Amagai in the tatami. Kenryū and Enryū rush to Rurichiyo to help her but Amagai soon breaks out.

Amagai goes to Yamamoto's desk and grabs the nucleus from Makoto Kibune's Bakkōtō. Feeding it to his own, the bakkutō's true form is revealed to be a black dragon shaped arm covering with many nuclei and a green glowing beam coming out of it. Yamamoto removes his haori and releases his Zanpakutō in retaliation. The flames spread wildly, destroying a portion of the room. Yamamoto sends flames towards Amagai but the traitorous captain stabs into them with his Bakkōtō, nullifying them to Yamamoto's surprise. Yamamoto questions how he did that and Amagai says that his Bakkōtō's power is to negate the powers of a Shinigami's Zanpakutō. Amagai then releases his Bankai and attacks Yamamoto, destroying much of the barracks and bringing the fight outside. When Amagai begins to threaten Rurichiyo, Yamamoto intervenes, saying he is the target. Amagai however says that he plans on taking the successor of the Kasumiōji Clan down with Yamamoto. He prepares to attack again but it interrupted by the arrival of Ichigo who slashes at Amagai.

Battle
Amagai blocks and Ichigo moves back as Rukia arrives as well. Amagai asks how they found him and Rukia says that Kenryū told them via a Jigokuchō. Ichigo then asks Yamamoto why he is not fighting back and Amagai reveals his Bakkōtō's ability to Ichigo. Ichigo then resolves that Amagai truly is an enemy and asks who he is. Yamamoto question how he knew Shin'etsu Kisaragi's name. Amamgai then reveals that Shin'etsu was his father.