After inheriting a large sum of money following his despicable parents' demise, a boy embraces freedom and immerses himself in the challenging online game 'Dungeon Attack.' Surpassing all players, he achieves the impossible by defeating every Demon Lord. Yet, his fate takes a twist when he answers a cryptic question and is transported into the game world. Reborn as the feeblest Demon Lord, 'Dantalian,' ranked 71st, he must navigate this ruthless realm armed only with memories of his past triumphs and his cunning wit. In a harsh world of survival, he embarks on a journey of resurgence and vengeance.