Lind had not grasped everything about how beasts decided borders, but it was generally accepted that barring an area a Heaven Realm could not use, the territory was at the range of the highest cultivation realm.
At that point, it came to when 2 beasts sensed each other at a distance. It made borders sometimes a fluid concept. Afterall, beasts fought and died everyday in the life of survival of the fittest.
It got a bit more rare in the Sky Realm higher tiers, but Star Tiers would sometimes fight it out to expand territory or simply their instincts demanded them to fight.
Lady Gua had been a relatively stable position in the Mengcong but letting Lind build a sect was likely to make ripples in all of the Wild Heart Isle. Ironically, Lind had calmed many aether beasts that had been disgruntled with his draconic roar on his first day there.
Now, they flew through the air to the edges of the current border.