Breakthrough with the Forbidden Master

Ten years after the war between humanity and demons concluded, the children of the heroes who saved the world have come of age. Among them is Earth, a talented young man expected to follow in his father's footsteps as a warrior. However, Earth harbors unease regarding his father's heroic legacy. One day, Earth discovers his father's legendary sword, instrumental in defeating the Demon King, sealed within his family mansion. The sword imprisons the restless ghost of the Great Demon King, who is unable to move on. Uniquely, Earth can perceive the Demon King's spirit, and it possesses him through the sword. Forced into an unusual cohabitation with the Demon King's spirit, Earth hears a casual offer: "I have a grudge against your father. If you want revenge on him and the world, I'll train you. I'm free." Driven by a desire to spite his parents and the world, Earth accepts this clandestine tutelage. This alliance sets the stage for a future where Earth's actions, guided by the Demon King, will profoundly impact his parents, past heroes, his first love, his childhood friend the princess, the era's geniuses, and the world itself.