Takatsuki Yua

A troublemaker who looks down and belittle any man, regardless if he's a student or a teacher. She's not a bully, but she is a prankster, and her teachers are bothered by her troublesome nature. Naturally, her pranks extend to the main protagonist, who is the dormitory manager.
She acts bossy and cocky, but she's just putting on airs. Her mental strength is actually quite weak, and hides with others when she is about to get hurt, and is easily depressed when she is insulted.