The Day the Demon King Spoke the Truth

In a certain world where humans and demons were in conflict, a hero and their companions defeated the Demon King, and peace was supposed to arrive... However, the Demon King, who was thought not to appear for another 100 years, showed up in just a week and sent a letter requesting a conference. In response, leaders from various nations and the hero's party convened. The Demon King appeared with their subordinates, and the conference seemed like it would end without incident, but the Demon King's bombshell statement shocked the world. The contents of that statement were... Due to loose plot settings and other issues, I judged that it was impossible to continue any further, and although it was forcibly done, I have concluded this work.