The hero's son and the ghost of the Demon King are the master and pupil!? Eirth, the son of the hero who defeated the Great Demon King, is troubled. Always expected to achieve great things, but unable to meet those expectations. No matter the effort he puts in, and the results he obtains, it's never enough for them. *"I'm a disappointment compared to my father" or "Don't you know you're the son of the hero!!"* Living every day like this, Eirth meets his destiny in the room containing the sword of his father, the hero. *"Interesting. I will train you. I have only free time now."* Eirth receives special personal training from the Demon King just to get back at his parents and the world. In the coming days, his parents, the heroes of the past, his first love, the princess childhood friend, the geniuses of the era, and the world will tremble before him. *Note: Includes two extra chapters.*

*“Compared to our time, the current generation just aren’t as reliable” they said, “Still, isn’t he the son of the Hero?”* How annoying. It’s been over ten years since the battle between mankind and the demons ended. The children of the heroes who saved the world are all grown up. One of them, Earth, was a talented man, and everyone expected him to succeed his father as a warrior and defend his country, but Earth was always wary of his father’s title. One day, Earth is shocked to find his father’s sword, which was used to overthrow the Demon King, sealed in his family’s mansion. Because trapped within was the ghost of the Great Demon King who was unable to pass on and continued to roam the world. For some reason, only he could see the spirit of the Demon King, and the Demon King possessed him through the sword. Every day, forced to coexist with the spirit of the Demon King, they live a strange shared life, when the Demon King whispers to Earth on a whim. *“I have a grudge against your father. If you want to get back at your father and the world, I’ll train you. I’m free.”* Earth receives special personal guidance from the Demon King just to get back at his parents and the world. Then, in the coming days. The hero’s parents, the heroes of the past, the first love, the princess childhood friend, the geniuses of the era, and the world will tremble.

Jarkray, the King of the Demon Realm. For thousands of years, he waged war against humanity, slaying countless heroes who challenged him. But at last, five female heroes with power surpassing even the Demon King appeared, driving Jarkray to the brink of defeat. Accepting his end, Jarkray offered them words of respect, calling them “five strong and beautiful warrior maidens.” In that instant, however, their demeanor completely changed. The truth was, after centuries of war, most men had perished, and these young women had absolutely no resistance to the presence of a male. Their maidenly hearts awakened, the five heroines abducted Jarkray. And thus, at the edge of the world where no one could disturb them, the Demon King’s bizarre “newlywed life” began.