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

He thought to himself, "To a Quasi Immortal Emperor, an Invincible Immortal King is just an ant that can be killed easily. Why did the Exalted Immortal ask me to follow him? With the cultivation of a Quasi Immortal Emperor, there's no need to use this to intimidate me, nor is it possible for him to do this just to let me see his strength… I understand. He's probably trying to give me an opportunity.

To be able to watch a Quasi Immortal Emperor attack at a close distance and observe the mysteries of time is a great opportunity for someone like me who is trying to step into the Quasi Immortal Emperor realm.

If my realm is high enough, it's even possible for my cultivation to directly increase because of this. I might even break through on the spot and reach the level of a Quasi Immortal Emperor.

But this is only the first time I've met this senior, and he actually wants to give me such a huge opportunity. What's the purpose? What's the reason? What's his goal?

Grand Seal Immortal Sky Net, A Brand New Law (2)