The demon realm, a haven of peace and philosophy, is on the verge of a war it doesn't want. The Demon Lord, a wise and kind ruler, believes a controlled and limited conflict is a necessary evil to protect his peaceful society from the ever-present threat of the power-hungry human kingdoms. While his court prepares for this necessary evil, his son, Oliver Albrecht Wainwright, harbors a different view.

Oliver is a paradox. A demon with the soul of a human, he carries the memories of his past life as Kōsuke Hayashi, a political science student whose life ended in senseless violence. He understands the insidious nature of human ambition in a way no demon can, knowing that "controlled" war is a lie that only leads to more bloodshed.

Now, Oliver must challenge his father's conventional wisdom. He will use his deep knowledge of political history and theory to forge a third path—one of cunning diplomacy and strategic negotiation.