Plot

Tired of endless war, Demon King Anos decides to be reincarnated into a peaceful future. Enrolling in school, he doesn't get the welcome he hoped for.

In the distant past, a war between humans and demons brought about widespread chaos and bloodshed. To put an end to this seemingly endless conflict, Demon King Anos Voldigoad willingly sacrificed his life, hoping to be reborn in a peaceful future. In preparation for their king's return, the demon race created the Demon King Academy, an elite institution tasked with determining Anos' identity when he reawakens. He reincarnates two millennia later, but to his surprise, he soon learns that the level of magic in the world has drastically waned during his absence. Moreover, when he enrolls at the academy to reclaim his rightful title, he finds out that demonkind remembers him differently. His personality, his deeds, and even his legacy are all falsified-masked beneath the name of an impostor. This "lack" of common knowledge renders him the academy's outlier-a misfit never before seen in history. Despite these drawbacks, Anos remains unfazed. As he sets out to uncover those altering his glorious past, he takes it upon himself to make his descendants recognize that their ruler has finally returned.—MAL Rewrite

Once upon a time, there was a man, who obliterated human countries, burned the forest of spirits to ashes and even killed Gods. The man was feared as the demon lord. However, even a demon lord gets tired of the horrors of war and proposes the heroes, who have come to negotiate with him, to kill him, split the world into four: the human world, the demon world, the spirits world, the world of the Gods, to build walls between the worlds, and to seal their gates for 1000 years. After 1000 years, the grudges between demons and humans should disappear. 2000 years after the demon king has finally been reborn and the new world truly shocks him. How has the world changed in 2000 years?—Scientiiaa

Anos Voldigoad was a tyrannical Demon King that eradicated humans, spirits, and even the gods, but became bored of eternal warfare and reincarnated with dreams of a peaceful world. However, what awaited him in reincarnation after 2000 years were descendants who became too weak after being accustomed to peace, and all sorts of magic that deteriorated to the extreme. Anos enters Demon King Academy that gathers and educates those who are viewed as the reincarnation of the Demon King, but the academy could not see through his true powers and ends up branding him as a misfit.—Crunchyroll