The story begins with the Demon Lord Anos Voldigoad convening a meeting in his castle, Delzogade, with the Hero Canon, the Great Spirit Leno, and the Creator God Militia. Anos proposes a peace treaty to divide the world into four realms: Human, Demon, Spirit, and God, separated by a thousand-year barrier. He intends to sacrifice his current body as the source of immense magic to enact this grand spell, planning to reincarnate later. Canon, after initial skepticism, agrees to trust Anos, recognizing his sincerity. The spell is cast, with Leno and Militia channeling their power into Anos, and Canon delivering a fatal blow with his holy sword, seemingly sacrificing Anos.
Two thousand years later, Anos reincarnates as a human baby named Anos Voldigoad, born to Isabella and Gusta. To his parents' astonishment, the infant Anos speaks immediately and quickly grows to the equivalent of a six-year-old using a growth spell. He discovers that magic has significantly regressed in this era, with concepts like reincarnation being unknown. Anos receives an invitation to the Demon King Academy Delzogade, an institution established to train powerful demon lords, specifically those descended from the "Tyrannical Demon Lord," a title referring to Anos himself. The academy seeks to find the reincarnated Anos, who is believed to be among the promising students of the "Chaos Generation."
Anos, accompanied by his worried parents, travels to the academy. Upon arrival, he encounters Misha Necron, a girl with platinum blonde hair and blue eyes, who is also an applicant. Anos's immense power is immediately apparent when he effortlessly defeats the arrogant demon duke Zepes Indu during the entrance exam, first by extinguishing his "demon flame" with a breath and then by incapacitating him with a mere heartbeat amplified by his magic. Zepes's brother, the demon emperor Liorg Indu, intervenes, attempting to kill Anos with his "Origin Magic: Demon Black Thunder Emperor." However, Anos reveals that Origin Magic draws power from its origin, and in this case, the origin is Anos himself, rendering Liorg's attack ineffective against him. Anos then demonstrates his power by reviving Zepes as a "Flesh-Rotting Undead" and forcing Liorg to confront his brother, highlighting the weakness of their sibling bond.
After Anos defeats Liorg and Zepes, the owl proctor declares Anos the winner and directs him to the Hall of Great Mirrors for further testing. There, Anos reunites with Misha, who expresses her fear of his overwhelming magic, particularly his "Flesh-Rotting Undead" spell. Anos then undergoes a magic power measurement, which causes the measuring crystal to shatter due to his immense power, resulting in a reading of "0" and a "measurement impossible" status. He proceeds to the aptitude test, which involves answering questions about himself and his past. Anos answers all questions flawlessly, demonstrating his knowledge of his own history, including the accidental destruction of Dilheid. He then invites Misha to his home for a celebration, using his teleportation magic, a lost art in this era. Misha, impressed by his power and knowledge, accepts. At home, Anos's parents are still adjusting to his abilities, while Misha observes his power with awe. The chapters conclude with Anos and Misha preparing for the next stage of the academy's admission process.
