Ouka Sayama is a Manyuu assassin and Muneyuki Manyuu's bodyguard who is sent by the Manyuu to chase after Chifusa Manyuu. She is cold and ruthless, showing no mercy against any foes. She is an incredibly skilled swords-woman, her skills matching and possibly even surpassing Chifusa's. After she lost her breasts, Ouka endured the harsh lifestyle of a flat-chested commoner until Muneyuki employed her, ignoring her lack of social position due to her small breasts as well as her love for him. She is chasing Chifusa in order to get back the Manyuu scroll and to overcome the loss of her breasts, which happened during her fight with Chifusa when they were still children. However, Chifusa eventually manages to give Ouka her breasts back through the Chichi-Nagare technique.
Ouka has very long black hair and wears a pink kimono with dark purple ends. She has black arm guards with dark purple wraps on her forearms and purple and white cloth on her upper arms.
Ouka is a quiet, cold woman who keeps to herself; as such, not much is known about her besides the fact that she is Muneyuki's bodyguard. Nonetheless, she occasionally shows a more compassionate side.
Swordsmanship: Ouka has been shown to be a incredible swordsman and arguably the best shown in action in the series. She was skilled enough that, on multiple occasions, she was able to cut Chifusa - or would have been able to were it not for external factors coming into play. She is shown to rely primarily on her speed in combat; she was fast enough to cut open the upper half of Chifusa's kimono before she could even react, leaving her so surprised by the attack's speed that even as her breasts were left on display to several villagers, she was too befuddled to cover herself up.
Ouka's usage of a Nodachi as her choice sword also aids her style, granting her greater range as well as leaving her foes wary of it.
Tracking: Ouka has been shown to be a remarkable tracker. She has managed to track down Chifusa on two occasions with help from her hawk.
- She is the only person in the series to wield a Nodachi.
- She is voiced by Mamiko Noto, who is known for playing Masane Amaha in the Witchblade anime.
- A recurring joke in the series is that, being one of the few women with a small cup size, Ouka’s breasts are constantly pulled and grabbed roughly; Ouka even happily does that to herself after recovering them.
- It seems that in the past, Kagefusa forced Ouka on numerous occasions to perform Chichi-Togi on her massive breasts. Not only does she have a nightmare about one of these occasions (Special 3), but in Special 4 she willingly restrains Chifusa under Kagefusa's orders stating, "Neither my body, nor my Soul can stand up to Kagefusa-sama."