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.