My Junior Sister Accused Me of Being a Demonic Cultivator? Well, She's Not Wrong

Any Short Stories with Characters Who Are Direct and Upfront? I'm Impatient and Don't Want Endless Will-They-Won't-They

An Invincible Protagonist Who Cultivates Demonic Arts

As long as it's about an invincible demonic cultivator, anything goes.

Looking for Stories About Demonic Cultivators

I want a story where the protagonist cultivates demonic powers. No female lead, no saintly protagonist, and someone ruthless and merciless. Can anyone recommend a few?