Eryton
Eryton is the capital city of the Terifall kingdom, located high in the Wendrock Mountains. It's a heavily fortified, and somewhat over engineered city with four defensive walls each one higher than the other as they close in around the primary citadel at the center of the city. It is also a city built on a hillside to maximize their defenses. The castle itself, as some might consider, is extremely overbuilt. Part of the reasoning behind this is that the lands of Terifall border on the territories where the giants of The Giant Mountains once roamed freely before the great wall was erected.
Prior to the complete extermination of all the giants in those mountains, there was always a risk that the giants might escape from the mountains and begin to terrify the land again as they had in ages past. As such, the castle was built to keep out giants, rather than regular invading armies, as it was very unlikely that a regular army would bother with attacking the land of Terifall given its location high in the mountains, and it's near borderline inability to supply even its own needs, let another nation's needs. As such, Terifall was of generally low value to most other nations, and thus in no risk of being invaded. Only the giants of the Giant Mountains posed it any real threat.
Later on, once The Race of Offworld was won, and the fifth hextant was abandoned, the castle was abandoned when the city was moved down into the richer, lusher lands of the fifth hextant where they could survive better and easier. Once the city moved, Eryton was converted into a local garrison outpost with the singular goal of protecting the few citizens of the kingdom who still remained up in the mountains around the old city.