Demon: Getting Weaker Without Limit, What Could Go Wrong?

[Western fantasy + multiple heroines + reverse leveling + multiple races + talents of the Seven Deadly Sins]

Li Ming transmigrates into a demon, only to discover that he has a talent that lets him grow stronger by absorbing magic cores. Starting as the weakest demon, he becomes the strongest in the world!

Except, not quite. When Li Ming discovers that his Creator can control him unconditionally, he realizes things are not that simple. His only choice is to keep growing stronger and fight against his fate of being controlled.

What Li Ming doesn't know is that his transmigration has caused the world's original timeline, which was supposed to be reset, to diverge. He has replaced the stories that belonged to other demons, and even done a thousand times better than they did.

The witches who reset the world are dumbfounded.

But as long as you can kill the Demon King, that's fine. Wait, how did you become the Demon King?

Elf Queen: Lord Black Demon King, please save our world, and save me as well.

Saint of the Church of Holy Light: No, you're a demon and I'm a saint. There can never be anything between us.

Angel Empress: Hmph, you despicable demon. Your thoughts are so vile that the Holy Light shall smite you!

Li Ming: Don't be afraid. After all, I'm not really a demon.

P.S. I'm terrible at naming things, so don't be misled by the title. It's only named that way because of the protagonist's skill, which is how he comes to rule the world.