Since Rosty is a [i]smal[/i] country, I'd say Niscenis have... 200,000 while Rosty has 120,000. Nisceni is a relatively new yet flourishing empire, so I expect troop training and numbers to be tip top.

Actually, the invasion would be blitzkrieg-style and Fayport would be overrun overnight. As the Nisceni advance further inland, the remaining cities in Forest Mither would form a resistance movement.

Estermere is a strategically important location because of the Astronomer's Guild and a massive supply of magic rock surrounding Estermere Berion has aptly named Berionite.