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

While Cui Heng was away, the Outer World had also tried to send experts over to establish a cross-border connection.

Because of the defense system constructed by the Three Higher Heavens with a portion of the power of the Heaven Realm, only by having a cross-border connection could the Outer World allow their Heaven Gate experts to infiltrate.

However, with an expert at the Sixth Heaven Gate realm guarding here like Hui Shi, no Outer World expert could hide from his perception. Whoever came would die.

As time passed, the Outer World temporarily gave up on establishing a cross-border connection here. It had been a while since they sent anyone over.

Taihong Star and the surrounding worlds also returned to a rare calm.

Cui Heng looked down at the ground below. Hui Shi and Pei Qingshu stood beside him and smiled. "From this perspective, Taihong Star can be said to be one of the most prosperous stars in the myriad worlds."

Reaching the Heavens, Ancient Sacred Body Heart