Mariko Higashiuchi

The "school sword action" story revolves around Magic Knights, modern magic-users who fight with weapons converted from their souls. Ikki Kurogane goes to a school for these Magic Knights, but he is the "Failed Knight" or "Worst One" who is failing because he has no magical skills. However, one day, he is challenged to a duel by Stella, a foreign princess and the "Number One" student. In this duel, "the loser must be obedient for life."

With the sudden appearance of the monsters that came to be called Dragons, the world had completely changed. Before long, within the human race supernatural girls with the power of the dragons, called "D," were born. The secret existence of the only male "D," the boy Mononobe Yuu, was forcefully thrown into the school where the girls of "D" gathered-Midgar, where he saw the naked body of one of the students, Iris. Furthermore, meeting his long-lost sister Mitsuki, Yuu seems to have been enrolled into this school...?! "When there's really no other choice, Iris, I will-kill you." "Can I really... believe you?" The curtains open as the "one and only story" about the boy who was supposed to become the strongest assassin and the incompetent girl unfolds-! Unlimited School Battle Action!