Ayaka Kankei is the adopted little brother who is a ghoul. Having a bad past he decides to go to anteiku who welcome ghouls with open arms. There he meets Touka and Ayato Kirishima two siblings who had to watch their dad die right in front of them. He was the first friend the two siblings made. Ayaka having an understanding of the low life ghouls have. When Ayato joins the Aogiri tree Ayaka goes with him. Having to watch his adopted mom work herself to death and then having to take care of his adopted little brother on his own. While Ayaka stayed at while being in the Aogiri tree he stayed away from his adopted little brother. Ken not understanding why just agreed to stay away from his older adopted brother thinking he was still taking the blame of their mothers' death.
4 parts