Set at the "Death Weapon Meister Academy", the series revolves around three teams, each consisting of a weapon meister and weapon that can transform into a humanoid. Trying to make the latter a "death scythe" and thus fit for use by the academy's headmaster Shinigami, the personification of death, they must collect the souls of 99 evil humans and one witch, in that order; otherwise, they will have to start all over again.
It is the Taisho Period in Japan. Tanjiro, a kindhearted boy who sells charcoal for a living, finds his family slaughtered by a demon. To make matters worse, his younger sister Nezuko, the sole survivor, has been transformed into a demon herself. Though devastated by this grim reality, Tanjiro resolves to become a “demon slayer” so that he can turn his sister back into a human, and kill the demon that massacred his family.
A samurai lord has bartered away his newborn son's organs to forty-eight demons in exchange for dominance on the battlefield. Yet, the abandoned infant survives thanks to a medicine man who equips him with primitive prosthetics—lethal ones with which the wronged son will use to hunt down the multitude of demons to reclaim his body one piece at a time, before confronting his father. On his journeys the young hero encounters an orphan who claims to be the greatest thief in Japan.
Ushio thinks that his father's talk of an ancient ancestor impaling a demon on a temple altar stone with the legendary Beast Spear is nuts, but when he finds the monster in his own basement, Ushio has to take another look at the family legend! To save his friends and family from the invading spirits, Ushio is forced to release Tora from his captivity. But will the creature prove to be worse than the curse?
Beelzebub is a great demon lord who rules over several millions of demons. Myurin, who decides to serve the demon lord, learns that not only does Beelzebub lack the poise of a great demon, but is also a laid-back girl who likes fluffy things. Thus begins the daily-life comedy revolving around the many villains in the demon world.
Lucy is a 17-year-old girl, who wants to be a full-fledged mage. One day when visiting Harujion Town, she meets Natsu, a young man who gets sick easily by any type of transportation. But Natsu isn't just any ordinary kid, he's a member of one of the world's most infamous mage guilds: Fairy Tail.
Staz is a vampire from the surreal "Demon World", and Fuyumi, an ordinary girl, accidentally wanders into the Demon World through a portal. Subsequently after meeting each other, Fuyumi is killed by a carnivorous plant and turned into a ghost, causing Staz to take responsibility and pledge to help bring her back to life.
The Amanto, aliens from outer space, have invaded Earth and taken over feudal Japan. As a result, a prohibition on swords has been established, and the samurai of Japan are treated with disregard as a consequence. However one man, Gintoki Sakata, still possesses the heart of the samurai, although from his love of sweets and work as a yorozuya, one might not expect it. Accompanying him in his jack-of-all-trades line of work are Shinpachi Shimura, a boy with glasses and a strong heart, Kagura with her umbrella and seemingly bottomless stomach, as well as Sadaharu, their oversized pet dog. Of course, these odd jobs are not always simple, as they frequently have run-ins with the police, ragtag rebels, and assassins, oftentimes leading to humorous but unfortunate consequences.