Soul World [1]
The situation in Soul World could be first defined with one sentence.
The first open betrayal of a major power.
It had been inferred since before the Beast Domain invasion that the Nox developed a way to counter Soul World's ambient mana, but the exact method was unknown until they actually broke into the Spirit Domain.
At that moment, people realized that what they thought was one was actually two!
The Nox had their own method to overcome the natural hurdle they faced. This method gave them the ability to traverse Soul World without being inhibited by the Sector, but they wouldn't receive any benefits either.
It was a method that had heavy restrictions on its use. Certain conditions had to be achieved, otherwise, they'd immediately lose their protection.
However, the second method covered for this weakness.
What else could it be?
Divine Soul Holy Land, the main influence that governed Soul World, sold themselves to the enemy.