Byakuya Kuchiki vs. Senbonzakura is a fight which takes place during the initial stages of the Zanpakutō Rebellion. It details the conflict between 6th Division Captain Byakuya Kuchiki and his Zanpakutō Spirit, Senbonzakura, and its outcome proves to be pivotal in later events.
As Rukia Kuchiki and 6th Division Lieutenant Renji Abarai run through the Seireitei, Renji curses and states the Zanpakutō spirits are destroying everything. When Rukia asks Renji if he believes everyone was able to escape, he confirms this and says there is no need to worry about the captains. As a portion of the building next to them explodes, Gonryōmaru emerges from the smoke and stands in front of them as Kazeshini appears behind them and laughs. As Rukia and Renji draw their blades, Renji asks Rukia how her Zanpakutō is.
Saying she cannot use her Shikai, Rukia states they are coming. As the two men leap towards them, Kazeshini leans in toward Rukia and chuckles before moving away as Gonryōmaru generates electricity along his pike and surrounds Rukia and Renji with lightning. As they leap into the air, Gonryōmaru appears behind Rukia and stabs at her. Meanwhile, Renji clashes several times with Kazeshini, who spins towards him before striking at him. Blocking the attack, Renji expresses concern for Rukia.
As Rukia lands on a roof, Gonryōmaru leaps into the air and prepares to attack her. Extending his arm and pointing at Gonryōmaru, Byakuya uses Bakudō #61. Rikujōkōrō, immobilizing Gonryōmaru in midair with six yellow spiritual bands. Seeing this, Rukia looks towards Byakuya, who stands on top of a nearby tower, and calls out to him. Calling out to Rukia, Renji asks her if she is alright before calling out to Byakuya.
Looking at them, Byakuya tells them to stay alert as Muramasa states he is right. As Rukia and Renji turn in surprise, Muramasa says the captains are very impressive. Standing beside Senbonzakura on top of a nearby building, Muramasa states they possess the strength to control powerful Zanpakutō as Senbonzakura steps forward and draws his sword, which glows pink before assuming its normal appearance. As Byakuya and Senbonzakura look at each other, Rukia tells Renji to be careful.
When the man reveals his name is Senbonzakura, Byakuya tells Rukia and Renji to leave. When Rukia begins to protest, Byakuya puts his hand on his blade and says he will not repeat himself. Moving away with Shunpo, he appears in front of Senbonzakura and slashes at him. Blocking, Senbonzakura jumps away as Byakuya leaps after him. As they clash several times in midair, Byakuya knocks Senbonzakura away with a powerful strike. As Senbonzakura lands on a nearby roof, Byakuya moves to him.
As they cross blades, Senbonzakura states Byakuya is an experienced fighter and proclaims he should know it is hopeless to challenge his thousands of blades with one sword. As Senbonzakura's sword separates into blade petals, Byakuya expresses surprise before moving away with Shunpo. As he lands on another roof and leaps away, Senbonzakura sends the blade petals after him and proclaims he cannot escape. As Byakuya lands on another roof and jumps away, the stream of blade petals rebounds off of the roof and surges after him.
Leaping into the air, Senbonzakura proclaims it is useless and sends the blade petals after Byakuya, who is engulfed by the petals. As Rukia calls out to him, the blade petals crash into a nearby building, destroying it. In an underground passage, Byakuya crashes through the ceiling and appears outside of the resulting cloud of dust with Shunpo before moving back as Senbonzakura appears.
Rushing toward each other, Byakuya and Senbonzakura clash. Moving to the side, Senbonzakura sends several streams of blade petals toward Byakuya, who fires Hadō #4. Byakurai to disperse them. As the bolt of lightning travels past his head, Senbonzakura expresses surprise as his eyes return to their normal size.
As Senbonzakura lands on the ground, Byakuya appears in front of him and points his blade at Senbonzakura, who refers to him as master. Noting Senbonzakura has returned to his senses, Byakuya lowers his sword and asks Senbonzakura what happened. Saying he does not know, Senbonzakura states he heard a voice coming from within his mind and reveals it told him to release his soul and follow his instincts. Saying he understands, Byakuya states it is as he feared. Afterwards, the two devise a plan to find and kill Kōga Kuchiki, Muramasa's Shinigami master, whose freedom is Muramasa's true goal.