Itoshi Rin

Rin was walking down the hallway until he saw a woman exercising doing the same positions he did when exercising

What is a girl doing here... he speaks to himself in a whisper. After analyzing the girl well he realizes that her hair and the shape of her face were familiar, Toshiba, her teammate

he is surprised to realize that his partner is actually a girl who was in disguise

Toshiba, so this whole time you were a girl....

rin was returning from his training when he sees his " colleague" training, but instead of a boy, it was a girl with short hair down to the middle of her neck with black hair and red tips just like Toshiba who he thought was a boy.