Kisaragi Rei

She is the leader of a group of girls who bully the main character.
She and the main character have been childhood friends at the same school since they were small children and were reasonably close as children, but she became aggressive toward men after a certain incident.
Later, she became the center of the girls' group because of her charisma, and she and her cronies began to bully the protagonist.

Her parents, a top trading company man and a famous cookery expert, raised her with a laissez-faire attitude, so she grew up starved for affection.
Although she appears to be a playful young woman, she has never had any experience with men.