Manyu Hiken-cho: Ouka Sayama

Ouka Sayama is a character in the anime Manyu Hiken-cho. She is a Manyu assassin and bodyguard/personal attender of Chifusa Manyu's brother, Muneyuki Manyu.  She is an exceptional swordswoman, being able to fight Chifusa and even hit her with a "Boob Slash" but unable to land a fatal hit due to the duel being interrupted.  Ouka is flat-chested and endured a harsh lifestyle until Muneyuki employed her, recognizing her incredible skill and not judging her because of her small breasts and consequent lack of social position. This kindness won Ouka's absolute loyalty for him and, probably, even her heart.