Keita Torigaya

Keita is Ryo Washizu's only friend until Washizu started opening himself to other people. Both in the anime and manga she started looking like a male, but chapter after chapter she apparently shrinks in size and shows more feminine traits. In the anime, her actual gender is suddenly revealed in the last episode, while in the manga the change is much more gradual, having the first hint towards her actual gender when she dresses as a maid in chapter 37. This change seems to be noticed only by Washizu.