Slaying Immortals Against the Current

Over-the-top version: A solitary killer emerges from the darkness and returns to the golden age of cultivation ten thousand years in the past. How will he survive in a world where fists aren't the only thing that matters?

Regular version: Tang Zheng unexpectedly travels from the Dark Age of the cultivation world back to its golden age ten thousand years earlier. Having known only how to kill, how will he make a decent living in a world of cultivation that depends on crafting artifacts, refining pills, and growing all manner of immortal crops?

Invincible version 2: You country bumpkins from ten thousand years ago, your daddy's brought ten thousand years' worth of unrivaled killing techniques to conquer this world! (Tang Zheng laughs like a fool.)