Isei finds new troubles about to enter into his life and two even sleeping in his bed. While looking at an old photo album of Isei's, Kiba sees a familiar sword being held by an old friend of Isei's, which reopen's old wounds. Meanwhile, Devils, Fallen Angels, and The Church's agents all clash to get their hands on, or just destroy, powerful weapons called Holy Swords. If that weren't enough, Isei's red dragon warns him that he senses his old rival the white dragon is drawing near.
The story follows Issei Hyōdō, a dim-witted, lecherous second-year high school student who is killed by a girl on his first date ever. Issei is reincarnated as a devil, and from that day forward, he serves as an underling of Riasu, a high-level devil who is also the prettiest girl on Issei's campus.
Misaki Ayuzawa is the first female student council president at a once all-boys school turned co-ed. She rules the school with strict discipline demeanor. But she has a secret—she works at a maid cafe due to her families circumstances. One day the popular A-student and notorious heart breaker Takumi Usui finds out her secret and makes a deal with her to keep it hush from the school in exchange for spending some time with him.
Takeru Ohyama, a young normal yet perverted minded guy, got accepted and now goes to a school that, unknown to him, was where combat and magic is used. On the first day, he meets again after three years: Haruko Amaya, his childhood friend, Inaho Kushiya, a girl who says she's his fiance, and Kodama Himegami, a blonde who wants to kill him. Finding out that there are many girls there that just don't like him, he is told that everyone there uses a special magic ability while using an item or weapon called a Maken. Later, he finds that no Maken is acceptable for him and doesn't know what to do, since in this school the students get into duels that showcase their magic and combat power, of which he seemingly has none.
Takeru continues his education at Tenbi Academy as part of the newly formed Security Committee. As a team with the other members they battle unscrupulous individuals who use their Maken for evil purposes. In the meantime, his libido and the conflicting romantic interests of the girls surrounding him complicate matters considerably.
There was a time when the Hachimitsu Private Academy was a revered and elite all-girls' boarding school on the outskirts of Tokyo but a recent policy revision is allowing boys into the student body. On his first day, Kiyoshi Fujino discovers that he's one of only five boys enrolled at the school. Completely overwhelmed by the thousands of girls on campus, the few boys find that their situation is less than ideal.