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.
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.
After experiencing a bizarre dream, Madoka Kaname, a kind 14-year-old girl, encounters a magical creature named Kyube. Madoka and her friend Sayaka Miki are offered the opportunity of gaining magical powers if they agree to make a contract with the strange little being. He will also grant them one wish, but in exchange they shall risk their lives by accepting the responsibility of fighting witches. Invisible to human eyes, witches are catalysts of despair in the areas they inhabit. An ally of Kyube, a magical girl named Mami Tomoe, befriends and encourages the two girls to accept the contract. For an unknown reason, another magical girl named Homura Akemi is determined to prevent Madoka from accepting the deal.
Kasuga Arata lived a normal life together with his childhood friend, Hijiri Kasuga, in a small town. However, everything changed on the day of the Black Sun, and a magus (mage) appeared before him. The Black Sun caused the Breakdown Phenomenon which destroyed the town where he lives. Because of this, his normal life was artificially reconstructed by a grimoire that his childhood friend had left. The appearance of the magus led him to a new life in the Royal Biblia Academy and meeting the members of the Trinity Seven.