If I don’t die soon, I’ll become the ruler of the demon realm!

If I don't die soon, I'll become the ruler of the demon realm!Summary: Humanity's strongest warrior was killed by demons amidst a battle and gained the power to reincarnate, but somehow did so as a demon. Only by dying he can go back to living as a human, so he committed suicide non-stop. But things turned out to be the opposite of what he expected