When Ling Du was six years old, the bronze mirror hanging high above the altar taught him two martial arts: "Heaven-Severing Sword Art" and "Soaring Dragon Rising Phoenix." The village elders said they were just the commonplace "Sword Drawing" and "Snake Step," but Ling Du remained convinced they were the world's finest martial arts. After

ten years of diligent practice, he barely reached the threshold. Just when Ling Du thought he was lacking talent, he fortuitously slew a demon and opened the door to a new world.

It turns out that slaying a demon grants a simulated lifespan. In an instant, he could simulate ten years of sword training. Even with even the most limited talent, a thousand years of simulation would complete the feat.

From then on, slaying demons and monsters became Ling Du's personal mission.

...

Many years later, were "Heaven-Severing Sword Art" and "Soaring Dragon Rising Phoenix" commonplace?