A Manyu assassin and Muneyuki's bodyguard who is sent by the Manyuu to chase after Chifusa. She is cold and ruthless, showing no mercy against any foes. She is an incredibly skilled swordswoman, her skills matching and possibly even surpasing Chifusa's. She was the first person that Chifusa used the Breast Flow technique on, accidentally stealing her breasts during a duel when both of them were young. After she lost her breasts to Chifusa, Ouka endured the harsh lifestyle of a flast-chested commoner until Muneyuki employed her, ignoring her lack of social position due to her small breasts. It is implied that Ouka is in love with Muneyuki because of this kindness.

(Source: Wikipedia)