Seymour traveled through time and space, becoming the most absurd and powerful demon king in demon history. However, he arrived too early. It wasn't until he encountered Celia, a challenger in his later years, that he realized he had traveled to the world of Fulilian. Even the demons' near-eternal lifespans are drawing to a close... One day, the aging demon king, Seymour, retired, intending to find a secluded place to spend the rest of his days. He encountered a disobedient demon slaughtering humans, and despite his aging body, he struggled to defeat it. Amidst the ruins, he discovered a little orange-haired girl—"One year old, just born, you encountered the progenitor of human magic, Volame. Your mission is to survive her." Seymour looked at the system he had been waiting for a lifetime. And the little girl, still a child, barely learned magic, lay dying on the ground...