The town of Trewe really only got started due to being along a major trading route, standing as the last stop between the Badlands and the rest of Vohemar. Strangely enough, it attracted residents partially from the general lack of monsters in the area. While the desert has its own dangers, most of the monsters that plague Vohemar tend to avoid the desert, due to the fact that sheer numbers won't help them survive in a harsher climate.
Trewe has built up quite a lot recently, as more and more people use it both as a starting and stopping point for caravans and now airships as they traverse the Badlands. Most of the city's revenue comes from businesses and other services here for travelers. Their airship docking tower, which was built only two years ago, has become a point of pride for the residents here - mostly thanks to the larger amount of people now trickling in. General pride for Trewe isn't too misplaced, since they're currently the biggest city located anywhere near the Badlands.