While the majority of Ashes takes place in the Denwoed, Pliridge and Druiron are the two cities that also play an important role in the story. Let's set up some basic similarities of these cities to start off with. First, both cities are ruling cities, which basically means that they are one of the larger cities in the territory of Khos, run by a ruling family and competing with other ruling families/cities for more power. Khos is divided up into ruling cities, with some merchant towns spread in between. As you might imagine, this situation makes it a pretty chaotic place to live. The ruling families live in a manor, usually somewhere close to the center of their city, although it can really be anywhere inside the city limits. Outside the manor, the cities are organized into typical sections (industrial, business, residential, etc.).
Now on to Pliridge, more specifically. Pliridge is Ember's birth place- the city her parents originally ruled over (before their untimely deaths, of course). Now, Lady Báev and her two daughters are the authority of the city. Pliridge is a relatively simplistic city. It's one of the larger ruling cities, but not the largest. Because Pliridge is close to the North Mountains, it has a harsher climate, which limits the growing season and makes the city's economic focus coal, stone, and minerals. Honestly, the best way to describe Pliridge is really a gray color scheme. It's dusty, it's straightforward, and because Lady Báev is kind of the worst, it's not the cheeriest place to spend your time. But, it is one of the more powerful ruling cities, with the potential for a lot more power to be gained.
As for Druiron, it's a breath of fresh air, especially for Ember. Druiron is where Ksa and his family live, and it is one of the wealthiest ruling cities. It's also a bit larger than Pliridge because this city does not suffer from the same limiting conditions brought by the North Mountains. Druiron also happens to be situated on the banks of the Maistal River, the largest river on the continent. In all the areas where Pliridge is dull and gray, Druiron is bright and clean and shiny. This city offers lively street fairs and a wide variety of trade goods. Druiron's wealth elevates it above Pliridge in appearance, although not necessarily in terms of morality.
So there you have it. A very brief overview of Pliridge and Druiron, both of which play an important role in Ember's adventure. Of course, there are many other ruling cities scattered across Khos, along with plenty of merchant towns, but those aren't important at this time. We'll get there.