Miyanohara Jun

A third-year student, famous within the school for cross-dressing as a boy. She's bisexual, attracted to both boys and girls, but generally prefers petite younger brother or sister types.

She has a history of clashing with Yumi over girls. She encourages Ena, who can't let go of her feelings for Masaki, to take him away from Yumi.

You might think it's out of resentment toward Yumi, but actually, she has feelings for Ena? And there's another motive too...