The Dark Faction Academy wasn't just a single area or place. The actual size of the land where the Dark Faction Academy was situated was fairly large. It was on its own separate piece of land that looked broken off, almost as if someone had made it that way on purpose.
The journey to the academy was up a large mountain, and then, when finally reaching what looked like the only flat piece of land, if one continued to follow the path, they would find a bridge made out of land.
Connecting from one side all the way to the land where the academy was, surrounded by a type of large mist-like area. It was quite the drop if one were to fall. However, even after crossing into the main area, one wasn't in the academy immediately.
The land surrounded by the mist was large enough to be the size of any other city in the Dark Faction territory, and it was treated as such.