Montecristo was a devil who, due to the betrayal of his subordinates, suffered defeat at the hand of humans. At the last moment, he was granted a final miracle. He succeeded in returning to the past before all of his misfortunes began. However, his body had shrunk in the process, and he was now the size of a small child... A demon, defeated by the world and abandoned by his subordinates... Knowing what the future had in store for him, he made up his mind. The only thing I can rely on... is the dungeon! And who the hell betrayed me anyway?!