Nether Spirit Forest Realm was founded by an ancient God King named the Nether Spirit God King.
The Nether Spirit God King was one of the God Kings who excelled in soul techniques. He was also the God King of the Nether King Tribe, an Ancient King Tribe.
This time, the Nether King Tribe had declared their occupancy of the Nether Spirit Forest Realm to prevent anyone else from going inside.
Those who trespass would be an enemy of the tribe.
The Nether King Tribe was an Ancient King Tribe with vast resources and background, so their declaration deterred many of the cultivators, so much so that there were no challengers.
Even the Conqueror Tribe and Emperor Tribe, who rivaled the Nether King Tribe, did not send anyone there.
There were a lot of Opportunities of Fortune on the Ancient Central Heaven Planet, and it was not worth risking war with the Nether King Tribe just because of some treasures.