Godō Kusanagi is a 16-year-old high school boy, who once killed the god "Verethragna" and acquired the title of "Campione" ("God Killer") when he was 15. Erica Brandelli is a 16-year-old Italian girl, who is a "Great Knight" of the magic society "Bronze Black Cross" and had fought together with Godo to defeat Verethragna. Godo doesn't like fighting but his title of "Campione" makes him get involved in battles against other Campiones and uncontrollable gods.
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.
Senō Natsuru is your normal, everyday high school student. However, he's been chosen to be a Kämpfer, who's objective consists on fighting other Kämpfer with either guns, swords or magic. However, there's catch—first, you can't chose if you're a Kämpfer or not, and second, you must have the body of a girl to use your powers.
Tokiha Mai and her sickly younger brother, Takumi, have received a scholarship to attend the prestigious Fuuka Academy. On the way, the ferry they are travelling on becomes the site of a destructive battle between two girls wielding apparently supernatural powers. This is only the beginning of their troubles, as Mai learns that she herself possesses these powers - the powers of a HiME.
Due to poor grades, Tsukune Aono, an average high school student, has been unable to get accepted into any private academy of his choice. By exceptional accident, the only school to accept him turns out to be anything but ordinary; the school is attended by youkai disguised as humans. Fearing for his life, he attempts to escape only to meet Moka Akashiya, a beautiful girl who just happens to be a vampire. Despite this, Tsukune decides to stay at the academy, hiding his human nature from students and teachers. Tsukune also discovers that when the rosary around Moka's neck is removed, her true nature emerges.