The location of the Starbreaker Empire was well known to all. They had no such thing as allies exactly but they had some areas settled by them to procure further resources as could be scrounged up for the demons.
There were a few treaties in regards to the citadel that housed the only known Immortal cultivators left in the Celestial Fields. They used the local villagers as fodder to keep the peace between them.
Each side got what they wanted in resources and turned a blind eye to any moral issues in the case of the Immortal cultivators. The Fiends got the souls they needed to increase their numbers from a place the Immortals did not care about.
On the surface, they had some battles about it but no one important was lost.
A few weeks ago, however, all hell broke loose.