"The Demon King and the Hero" is adapted from a fantasy novel written by Japanese novelist Asami Akino. One day, a "hero" with great power broke into the Demon King's castle and challenged the Demon King to save the human world. However, what was waiting for him was a "demon king" who looked very similar to a human woman. The demon king did not choose to go to war with the hero, but wanted to make a contract to make the hero her property. Facing the hero who refused and asked for a duel, the demon king began to calmly analyze the actual situation between humans and demons to the hero, analyzed the fact that the current social order depends on this war, and analyzed the truth that even after defeating the demon king, the source of this war cannot be fundamentally solved. The demon king himself hopes for new possibilities-neither the tragic ending after the war ends, nor the continuation of the war. After understanding why the demon king needs his help, the hero decides to accept her contract and help her fulfill her wish. So, the hero and the demon king hide their true identities and begin to reform the world in the name of a swordsman and a scholar.