Otonashi awakens only to learn he is dead. A rifle-toting girl named Yuri explains that they are in the afterlife, and Otonashi realizes the only thing he can remember about himself is his name. Yuri tells him that she leads the Shinda Sekai Sensen (Afterlife Battlefront) and wages war against a girl named Tenshi. Unable to believe Yuri's claims that Tenshi is evil, Otonashi attempts to speak with her, but the encounter doesn't go as he intended. Otonashi decides to join the SSS and battle Tenshi, but he finds himself oddly drawn to her. While trying to regain his memories and understand Tenshi, he gradually unravels the mysteries of the afterlife.
This world consists of two dimensions joined as one, like a mirror. The first is the world in which the humans live, Assiah. The other is the world of demons, Gehenna. Ordinarily, travel between the two, and indeed any kind of contact between the two, is impossible. However the demons can pass over into this world by possessing anything that exist within it. Satan the god of demons, but there's one thing that he doesn't have, and that's a substance in the human world that is powerful enough to contain him!! For that purpose he created Rin, his son from a human woman, but will his son agree to his plans? Or will he become something else...? An exorcist?
Natsume Tomoharu is a normal high-school student in every way with one exception: he's being followed by the ghost of his best friend, Misao.After moving into his brother's old house, Tomoharu expects to continue living his normal life but is one day left with a mysterious and locked briefcase without any instruction. At first he plans to leave it in storage; however, his house is soon invaded by multiple groups of people after the briefcase. Although still not knowing the purpose of the briefcase, Tomoharu and Misao attempt to escape with it.From there on, Tomoharu tries to learn the secrets behind the briefcase, the connections between it and Misao, and why it has the power to change the world.
Following the first season, Tomoharu is now faced with a dilemma: if he doesn't form a contract with an "akuma", he risks losing his dear friend Takatsuki. However, doing so would compromise his own existence as it would result in him and his ghost friend Misao becoming an Asura Cryin'—mankind's biggest threat, according to their school's presidents. To make the decision even harder, Tomoharu and Misao have recovered some of their past memories—memories of a world that they didn't even know existed.
The story follows the "strongest juvenile delinquent", Tatsumi Oga, a first year in "Ishiyama High" the school for delinquents. One day while sleeping next to a river he sees a man floating down it, he pulls him to shore and the man splits in half revealing a baby boy. This boy is the son of the demon king and he has been chosen as the one to raise it with the baby's demon maid Hilda. The story follows his life with the child and at the delinquent school.
Okajima Rokuro is a Japanese businessman in a town full of Japanese businessmen. His normal day consists of social drinking with clients and being kicked around by his bosses. He finally gets a break though, as he's sent by his company to the tropical seas of Eastern China to deliver a disc. But his boat gets hijacked by a band of mercenaries hired to retrieve the disc. Rock (as he is newly dubbed by his captors) catches the interest of the only female merc Revy as she thinks he's worth a ransom, taking him hostage. However, the disc that was stolen has a terrible secret that's unknown to Rock, which causes massive confusion and chaos for both him and his kidnappers.
Okajima Rokuro - now known almost exclusively as 'Rock' - was once a typical, put-upon Japanese businessman. Then, on a routine business trip, he was kidnapped and ransomed by the Lagoon Company: a band of mercenary pirates operating out of the crime-riddled city of Roanapur. Abandoned by his bosses, he joined the Lagoon Company. Now he must try and stay afloat amongst the ever-shifting politics of the criminal underworld, while simultaneously avoiding death at the hands of his quick-tempered, gun-toting co-worker, 'Two Hand' Revy.
The story is set in a fictional Germany and centers around the outbreak of biomechanical creatures named "Demoniacs", who rise from corpses and attack people mindlessly. The Demoniacs have the ability to merge with most technology including cars and motorcycles, not only gaining control of them but also enhancing their performance greatly. Against them is a group of people known as XAT, Xenogenesis Assault Team, who police these Demoniacs in an attempt to keep the peace and discover the reasons for the "Demoniac" change. All the while, a number of human-turned-Demoniacs appear. Some use their powers for good whilst others for evil. One will rise above all other Demoniacs to become the "Blassreiter".
Saya is a seemingly normal girl living with her father in a shrine. During the day she goes to school and spends time with her friends at a local cafe. But when night falls Saya is called upon to protect her village from strange monsters.
Hasegawa Kodaka has transferred schools, and he's having a hard time making friends. It doesn't help that his blond hair tends to make people think he's a delinquent. One day, he runs into his bad-tempered solitary classmate Yozora while she's talking animatedly to her imaginary friend Tomo. Realizing that neither of them have any actual friends, they decide that the best way to alter this situation is to form a club and start recruiting. That is how "Rinjinbu", The Neighbours' Club, was formed, a club specifically designed for people who don't have very many friends. As other lonely classmates slowly join their little club, they'll try to learn how to build friendships through cooking together, playing games, and other group activities. But will this group of relationship-challenged misfits really be able to get along?