Byakuya's Betrayal

Mayuri experiments on Gegetsuburi, and discovers that the zanpakuto only return to their owners' control if they are defeated by their owners. Momo and Rangiku send their zanpakutos back to the 4th division barracks, but an unknown assailant attacks the cart carrying them. Ichigo meets with Momo and Rangiku, and then reaches Muramasa, who is having difficulties using his abilities in his current body. Ichigo attempts to attack Muramasa but is stopped by Senbonzakura. Ichigo fights Senbonzakura, and gains the upper hand before Byakuya arrives. Byakuya reveals that he has joined Muramasa as part of following his internal desire to protect his pride, and then disappears with Muramasa and Senbonzakura.