(Hero X Demon King) The Mischievous Demon King

The Demon King Feng Shizang was defeated by an alliance of elves and humans. An unknown number of years after his death, the Demon King was reborn in the body of a half-demon.

After being reborn, the Demon King meets a descendant of the demigod hero who once defeated him, though he doesn't know it. Before long, he discovers...

Why does something feel off? Why does this human have so many traits in common with his old nemesis?!

To see the light of day again and become the great Demon King he once was, the reborn Demon King hides his identity and sets out on the path to becoming stronger.

You want to know if it goes smoothly? How can you call it smooth when that little brat (the hero himself) keeps following you around?!

Feng Shizang (Cannavaro): Get lost, you hear me!

Richter (Vincent): No... QAQ

Feng Shizang (Cannavaro): ... (We hadn't seen each other for over four hundred years. How did this guy turn into a crybaby??)

Richter (Vincent): Hug me~ QWQ

Feng Shizang (Cannavaro): ... Get lost.

Tsundere Demon King bottom x black-bellied, innocent-looking, reborn Hero top

★ Another random idea. Don't read if it's not your thing~