Castlevania

The “Seven Deadly Sins”—a group of evil knights who conspired to overthrow the kingdom of Britannia—were said to have been eradicated by the Holy Knights, although some claim that they still live. Ten years later, the Holy Knights have staged a Coup d'état and assassinated the king, becoming the new, tyrannical rulers of the kingdom. Elizabeth, the king's only daughter, sets out on a journey to find the “Seven Deadly Sins,” and to enlist their help in taking back the kingdom.

The Private Aichi Symbiosis Academy was originally a high school for high-class girls. When it became co-ed, the girls, out of fear, asked to be permitted to bring weapons to school. When that was enforced, a five-member vigilante corps-like organization called the "Supreme Five Swords" was also formed. After many generations, the five swords eventually became a group which corrected problematic students, and the academy started proactively accepting such students in order to correct them. Nomura Fudou was sent to this school after being part of a huge brawl. What will he do when the only options he has after enrolling are being expelled from that school or being corrected the way the rest of the male students there were...by being forced to dress and act like a girl!