Monopolized

While a Mystical World could only be created with the power of an individual, a Legacy World received the help of the Heavens to be created!

Why was it that mere saints and celestials who barely grasped any sort of spatial laws could create Legacy Worlds? Why was it that the Mortal Clan could survive in those Legacy Worlds that opened on Earth for so many years despite being so weak? It was because the Heavens were fair.

When a cultivator reached the end of his lifespan, he was the most connected with the Heavens he would ever be. In that state, they're able to project their will to allow the Heavens to construct a method for them to pass on their knowledge. If it wasn't for this fact, every Legacy World would be formed by nothing but Peak Dao experts and Higher Existences!