Mizuki Kotori

A classmate of Ryouji's and friend to Yuuki and Shana. She seems a bit timid but is actually strong-willed with many friends. She seems plain and subdued and doesn't stand out much. She's always been part of the fetish world and schemes to provide Shana and Yuuki with skimpy costumes.

Spoiler

She's yearned for Ryouji for some time but hasn't approached him due to the competition. If you decide to approach you'll find her taste in sex is actually a bit abnormal, known to continue fellatio sessions for an entire night and say "thank you" for every caress.