Kenka Bancho Otome -Girl Beats Boys-

Hinako Nakayama has grown up in state-run orphanages, never knowing anything about her family. On the verge of starting high school, she’s confronted by Hikaru, a boy who insists he’s her twin brother—and that they’re both connected to the formidable Onigashima yakuza clan.

Hikaru asks Hinako to trade places with him at Shishiku Academy, an all-boys school ruled by the country’s toughest delinquents. Disguised as a boy, Hinako is thrown into a world of fights and martial arts as she tries to protect her brother, navigate unexpected feelings, and rise to the top of the school’s brutal hierarchy.