Evolution?! The Menace of the Final Sword Beast.Kazeshini attacks a cleaver sword beast that has been cornered by the ninth division, but the cleaver sword beast turns back into sword form before Kazeshini prepares for a fatal blow, confusing him. Kazeshini, Zabimaru, Hōzukimaru and Ruri'iro Kujaku gather together to discuss that a unknown sword beast is absorbing the spiritual energies of other sword beasts, causing them to turn back their sword forms. It is shown that the unknown sword beast has done this to a yōkai sword beast. The next day, the unknown sword beast attacks a lion sword beast, a face sword beast and an ape sword beast in the streets of the Rukongai, absorbing each of their spiritual energies. All of the zanpakutō decide to face this sword beast, recognized as Kirikaze, without their owners. They soon realize that their attacks are no match against Kirikaze due to his ability to transform into mist. Their owners arrive and convince them that Soul Reapers and zanpakutō must fight as one in order to win the battle. All of the zanpakutō give what little spiritual energy they have left to Renji, who is then able to activate his bankai, finishing Kirikaze off once and for all. Although the zanpakutō return to their sword forms, the Soul Reapers note that they can still feel the presence of their zanpakutō.