Kyouken is a character from the Katanagatari franchise.
She is a member of the Maniwa Corps' Beast Squad. When she finds out that Togame may be responsible for the death's of her teammates, she seeks her out for revenge despite the truce that Houou made with Togame.
Kyouken is a character in the Katanagatari series of light novels written by Nishio Ishin, a popular Japanese writer, with illustrations by Take. He also appears in the anime series of the same name which was created by White Fox and directed by Keitaro Motonaga. Kyouken, voiced by Michiko Neya, makes his first appearance in Episode #6 of the anime series: "Kanazuchi, the Twin Sword".
Kyouken is actually over 2,000 years old and has managed to stay alive using her Kyouken Hatsudou technique, which allows her to inhabit the body of a female and retain their memories. A side effect of the ability is that it creates purple tattoos all over the host body.
By using this on female ninjas, Kyouken has amassed a vast amount of battle knowledge and skill.