The Evil Ghost Realm is an ultra-large array designed by the Unpredictable Ghost Sect, capable of covering tens of thousands of miles, filling the entire region with Evil Qi, creating a world akin to a ghost realm.
The reason the Unpredictable Ghost Sect wants to go to war with the Wanhua Demon Court is to establish the Evil Ghost Realm in the Wanhua Mountain Range.
Establishing the Evil Ghost Realm requires a large amount of white bones, not ordinary bones, but bones containing Spiritual Energy, which are the bones of cultivators or demon beasts and Mutant Beasts.
If it were just about claiming territory, no one within the four domains of Wanhua could stop the Unpredictable Ghost Sect, but the issue is that the four domains of Wanhua cannot provide enough white bones for the Unpredictable Ghost Sect.
