August 31, 2012 (Japanese)
Insurrection (Hangyaku 反逆) is the twenty-first episode of the Accel World Anime. It aired August 31st 2012 in Japan.
As they make their way to meet up with Yuniko, Haru explains to Takumu how Seiji had set him and Chiyu up. After hearing about their situation, Yuniko agrees to teach Haru and Takumu about the Incarnate System, explaining the different skills that can be performed with them. As the type of skills an avatar can learn depends on the user's personal traumas, Takumu explains how he was bullied in elementary school, even leading to getting a scar, which gave Cyan Pile the Enhanced Armament, «Pile Driver». As Yuniko begins training Takumu, Haru is joined by Yuniko's ally, Blood Leopard, who takes him to Akihabara to investigate how Seiji hides from the matching lists. They arrive at the Akihabara Battle Grounds, a fighting arena for Burst Linkers which is also having troubles with an unlisted Burst Linker called Rust Jigsaw.