Sole Cloud Flying Cave

Cui Heng was transmigrated to another world and the system told him that the new world he was in was a high-grade Xianxia world.
It was a world where Celestial Kings soared the sky and terrifying monsters ruled the lands. The strong would destroy a planet if their mood was bad and Cui Heng trembled in fear when he learned of how scary the new world was.
Thankfully, the system had granted him the protection that last for 300 years. As long as he remained in the safety zone, he would not receive any damage.
With his safety secured, he began his cultivation training for the next 300 years.
Throughout the years as he trained, some people entered his safety zone by mistake.
There was a peasant who was once a monk and a beggar. Despite that, he still had the dream of bringing peace to the land and saving the lives of millions.
There was a noble who was once called the once-in-a-million-year genius. Yet, luck wasn't at his side and his talent fell and was laughed at by others for years.
There was a princess whose only wish was to find her older brother. She could've become a celestial but decided to remain in the human realm to wait for her brother's return.
There was a weak lady who was plagued with illness from birth but had the goal of adventuring and helping the poor and weak.
...
Cui Heng befriended these people and even gave them a few pointers before they left.
300 years later, when the protection period had ended, he had finally mastered the Golden Core. Even then, he was still reluctant to go to the outside world.
But when he did, he realized that the world was merely a world of Wuxia.

Realizing This Is A Wuxia World After Cultivating For 300 Years

It was true that the universe that discovered the Heaven's Will might not be the universe that was born from the Heaven's Will. Even if this universe was destroyed, it might not be able to kill the Heaven's Will. However, to the Primordial World, it was enough as long as there was a faint possibility. In any case, it was only destroying a universe in the Chaos Sea and had no effect on the Primordial World.

The envoy sent by Cheng Shang knelt on the ground respectfully and kowtowed to a man sitting on the jade platform. "…Supreme Venerate Wujue, that's what happened. Immortal King Cheng Shang requests you to take action and destroy that universe."

Wujue was a middle-aged man wearing a pure black robe, giving off an extremely deep and unfathomable feeling.

Legacy of the Supreme God of Heaven, The End of the Path to the Return to Void Realm (2)