Mikage Shana

Ryouji's cousin and classmate, and Yuuki's younger twin sister. She is the polar opposite of her sister, with a bright and cheerful personality brimming with curiosity. She treats Ryouji as naturally as he was her brother, and is devilishly cute, though not spoiled or calculating. She works part time as a fashion model, and immidately takes to the fetishism of the new world where she finds herself.

Spoiler

She likes Ryouji but is afraid of being rejected so she hasn't confessed to him.

While being very naughty and interested in sex, she's actually still a virgin.