After being defeated by the Hero from another world, the Demon King went to sleep, declaring that he would resurrect in a hundred years. 　—And after a hundred years… 　As he had declared, the Demon King has resurrected. However, the world has changed in the hundred years since then. 　”Wh-What…!” 　”So, the demon tribe and humans have made peace with each other and are living peacefully together now.” 　The Demon King is unexpectedly dismissed from his position. The former Demon King, now a mere demon, decides to become an alchemist in order to survive. To survive, I need food. To buy food, I need money. If I don’t work, I can’t survive! 　Thus, the former Demon King, who has the strongest power and the best alchemy skill in the world, shows his original unreliable nature to save the world!