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

Zhuo Fan did not know what the Heaven Pass was, nor did he dare to ask. He could only kneel there and tremble without saying a word.

After a while, the voice sounded again.

"Forget it, I won't waste my breath on you. Now that the spatial shackles have loosened, I've already obtained the opportunity to return to the mortal world. In a few days, I'll split my divine sense and reincarnate into the mortal world.

"You have to be prepared to welcome my reincarnation. At that time, I will give you the power of the Heavens and let you become the Lord of the Heavens of the Eighth Realm of the Immortal World."

After saying that, there was silence. There was no mention of the consequences if Zhuo Fan did not do as he was told.

However, Zhuo Fan did not dare to disobey.

The Old Man Who Sell Incense in God Cui Temple