The Hero's Blade of the Evil Dragon King

A clichéd story. A chuunibyou story.

When the war between the Demon King and the Hero is interrupted by a dragon that suddenly appears, the two have no choice but to join forces against it.

Then, one day, after a thousand years of war between dragons, demons, and heroes, the entire Demon King clan vanishes in an instant…

In the blink of an eye, the world has become an advanced dragon civilization. Those who possess the power of dragons rule the world. They are known as "Dragon Knights."

In this world, where will the last Demon King, Shinku Yoru Yui, go from here? What choices will he make?