A 34-year-old hikikomori is kicked out of his home by his family after the death of his parents. After his eviction, he saves a group of teenagers from being killed by a speeding truck, but loses his life in the process. When he comes to, he realizes he has been reborn as Rudeus Greyrat, in a world of swords and sorcery.
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.
For a thousand years, the Vikings have made quite a name and reputation for themselves as the strongest families with a thirst for violence. Thorfinn, the son of one of the Vikings' greatest warriors, spends his boyhood in a battlefield enhancing his skills in his adventure to redeem his most-desired revenge after his father was murdered.
