Mikage Yuuki

Ryouji's cousin and classmate, and Shana's older twin sister. She moved from her home town in the country to attend Seiai Academy. She gets good grades and loves to excel at everything, so when wearing costumes becomes the norm she wants to be the best at that, too. As a cool beauty she has received many confessions, but turned them all down,

Spoiler

harbouring a secret interest in Ryouji;

she's actually quite curious about sex, having heard all sorts of rumors, but doesn't like play that "ruins the mood".