It's been 100 years since ordinary people turned into livestock to live as hunters' slaves.One day, while training hard to become a hunter to fix this unreasonable situation, I was attacked by Eden's Athena, who wanted my "Diary of the Demon King."Thanks to the powers of my mentor, Sungkoo, I succeeded in going back 100 years ago, but then a message appeared in front of me."I, the Sky of Apocalypse will be your sponsor". The Sky of Apocalypse who had sponsored the Demon King? Then..."I'll become the player!"