The Heavenly Realm!
It was not a giant island suspended in the void.
Instead, it was formed by the overlapping of numerous Great Chiliocosms forcibly carved out by saints using boundless divine power.
The worlds were arranged vertically.
This was the so-called Thirty-Six Heavens.
The further back a heavenly realm was, the denser the heaven and earth spiritual energy, making it more suitable for cultivation.
However, the final few heavens were unsuited for immortals to enter.
The spiritual energy there was far too dense for ordinary immortals to digest at all. Under such circumstances, there was no benefit whatsoever.
In a sense, the final few heavens were absolute death zones for ordinary immortals.
The spiritual energy automatically generated within heaven and earth was sufficient for self-circulation.
Yet as the number of immortals grew ever greater and their realms ever stronger, the spiritual energy began to be replenished.
Thus Hongjun gathered all immortals to open up heaven and earth in the Outer Heavens.
Then Hongjun actively guided the chaotic qi of the outside world inward.
Chaotic qi was an extremely dangerous energy, and ordinary immortals would have their forms and souls obliterated upon touching it.
To let chaotic qi in without any treatment whatsoever was entirely an act of world-destruction.
These Thirty-Six Heavens were actually thirty-six filtering nets.
Passing through the dojos where several saints resided, the chaotic qi could be transformed into heaven and earth spiritual energy.
Yet the spiritual energy at this time was still like poison to ordinary living beings.
Even so, the heaven and earth spiritual energy was still not enough.
In this world's immortal cultivation system, one could achieve the same lifespan as heaven and earth simply by becoming an immortal.
As a result, the population became excessive.
This forced the Heavenly Dao of this world