In a world where humans and demonfolk are constantly at war, the all-powerful Demon King Anos Voldigoad tires of the endless bloodshed. He proposes a truce with the hero: divide the world into parts to separate the two races for a thousand years. Voldigoad then allows himself to be killed with the plan to reincarnate two thousand years in the future, hoping to be born into a better world.

He indeed reincarnates in a more peaceful era, born as a baby of two loving human parents. He receives an invitation to enroll at Demon King Academy, whose task is to find the reincarnated demon king as it is known that the reincarnation will occur this year. With his unrivaled powers, Voldigoad fully expects to be instantly recognized.

However, he is however promptly deemed "unqualified"; over the centuries, the tales about his personality, deeds, and even his name have been so distorted that there is not even the slightest resemblance as to who and what he once was. While annoyed, Voldigoad still expects that others will recognize him for what he is. More importantly, something else bothers him: the demonfolk and their magic have regressed so much that he is rendered dumbstruck, and most striking of all, his former lich lieutenant no longer seems to recognize him. Dark forces seem to be at work to prevent him from taking the helm of the demons. But to protect those dear to him, Demon King Voldigoad is ready to even defy providence if he must.