The Demon King Has Gone Softhearted Again and Again

Demon King x Hero. Major warning: first-person narration.

Originally, this was supposed to be a story about a Demon King who lived long enough to retire, but that sounded too boring, so our Demon King, namely me, went looking for trouble by messing around with the heroes. Then I got into a mess and had to take on the gods. Fine. The Demon King fought the heroes, and just when I was about to win, the Saintess started sobbing and yelling that she was a god. One grand feat later, I got smashed to pieces. Fine, I already had a bunch of debuffs and had been tortured to hell, so dying was no big deal. Except I was reborn. Fine, I was reborn back to before any of this had happened, so now I had to turn the tide. Fine, I got smashed to pieces again. Fine, I was reborn back to before any of this had happened, so now I had to turn the tide again… Am I really going to get smashed to pieces again? Fine, let me get smashed, but why are you putting your hands all over me, you little punk?

Wait, what if I stop trying to save myself? What if I just fall in love? No, I'm still going to get smashed to pieces? I transmigrated here just to enjoy dying? What do you mean I wasn't transmigrated? Then what am I supposed to do? I'm really going to be shattered.

Here's the serious synopsis:

One is the Demon King, bearer of the gods' wishes and burdened with their "blessing."

Immortal and undying, trapped in endless reincarnation. He slaughters humanity and destroys holy temples, but still never reaches the end.

The other is a forgotten anchor, never part of the ordained path.

He bears the memories of hundreds, even thousands, of deaths, watching as the Demon King's obsession grows madder with each return.

Every cycle tries to mend the regrets of the last, yet only brings deeper despair.

The two struggle again and again between slaughter and embrace, until love and flesh alike blur into one.