In a realm occupied by seventy-two feudal demon lords striving for supremacy, the youngest and weakest contender, Ashtarot, emerges with a unique advantage—a past life as a human researcher. Lacking traditional might and armies, his strength lies in his practicality. Employing ruthless strategies like eliminating potential heroes early and resorting to deceit, Ashtarot, the 72nd demon lord, seeks to outmaneuver his rivals to claim the title of Demon King. With his loyal demon maid Eve and followers by his side, Ashtarot gains notoriety for his unorthodox approach, earning a reputation as the demon lord unafraid to employ any means necessary, all in the pursuit of victory through the power of realism.