Fragmentation (Bunretsu 分裂) is the seventeenth episode of the Accel World Anime. It aired August 3rd 2012 in Japan.
As Haru contemplates how to go about facing Seiji, he receives a video call from Kuroyukihime, who mentions giving some information about Seiji to Takumu. During gym class that day, Takumu challenges Seiji to a battle, revealing he knew about Haru's ability being stolen. Although Takumu initially gains the upper hand, Seiji uses the incarnate system to give himself powerful arms and overwhelm Takumu. Haru manages to trick Seiji into switching to Battle Royale mode so he can fight against him instead, managing to cut off one of his arms with his own incarnation attack. As Seiji activates Haru's wings and some pyro equipment, Haru equips Sky Raker's «Gale Thruster», allowing him to take to the skies and face Seiji head on and manages to beat him with assistance from Takumu. However, before Haru can finish him, Chiyu appears and heals Seiji.