Phantom Peak was not totally isolated. It was part of a small set of peaks that were relatively barren. They did make a good launching point for the roost of various beasts, however, so they were a natural defense for Annabelle.
It helped that they respected both Kora and Lind's requests. He had not used his True Lord status even, just being a Divine Dragon was enough!
Thus, Annabelle had lived in relative peace for 500 years.
The tradeoff, however, was that the other peaks were then not as well defended from subtle infiltration.
Ethry and the 2 emerald dragons with her had routed most of the spies in the area. Some were simply spies just keeping an eye on an important figure. Not all spies were bad either as they sometimes relayed information to the Frey Clan from ally power.
A select few, however, had been found to be at the order of their new enemy.
