My Game Saves Become My System

XXX, who died of illness in the hospital bed, traveled into a novel he loved and started a new life in a different world called "John Astorea". The good news is that this novel has been adapted into an open world RPG game, and he happens to be a fully accomplished liver emperor. The better news is that this archive has become his own cheat system. The magic that others cannot use even if they try their best, turns out to be the most common ordinary attack in his own hands. Others relied on the system and the panel to travel through time, but he relied on staying up late to create the perfect save file! "Don't be afraid, I'm just an ordinary person. I don't have the power of a demon king, and I don't know all the magic in the world." He said this when facing the oldest demon king in the world. After saying that, he looked at the demon in front of him, grabbed it, and refined it instantly.