Hikawa Rei

Her father is the director of the school and donates heavily to the school, resulting in her becoming an arrogant and high-handed young lady who brings bodyguards and a tennis coach to the school.
She looks down on the protagonist and insults him at every opportunity.
She is the one who gave the protagonist the nickname "Squid Man".
She has a high sense of pride, but has the ability to match it, and spares no effort to improve herself.
She is a member of the tennis club, and her skills are among the best in national tournaments.