Isurugi Nagisa♀

She is Yuuto's cousin and fiancee. She is a beautiful girl with an old-fashioned and dignified appearance as the daughter of the Isurugi family, a famous family that were once former daimyo.

Her fearless looks make her difficult to approach, but she is full of emotion due to her hawkish personality. She is the captain of the naginata club, and despite her strict leadership, she is well-liked by her club members. She is an honor student with her strengths in literature and martial arts, she never neglects her studies even in her busy life.

In junior high school, a trivial incident awakened her to anal sexuality, and she was caught between her father's oppressive sex education and her desire for anal sexuality, which gradually made her unhappy. When her beloved fiance, Yuuto, accidentally discovered her sexual proclivities and interest in anal sex, she became even more anal sex crazed than ever.

[From official site]