Dug too deep unearthing Thri-Kreen invasion. Use magnetism. Old mining tradition. After long nomadic treks and running from horrible hulking creatures, dwarves finally made a stand at a cave mouth at the base of a mountain. This was the only place they were remotely safe from the elements and creatures on the outside and inside of the cave. Here they built the foundation for their city, The Stand
High up overseeing the lands the dwarves carved a giant wedge-like chunk out of the mountain; upper class and important structures were built into the face of the mountain. The city it overlooks is contained behind high walls in the shape of truncated crescent which lead back to the mountain. There are gauss cannons dotted along the edge of the wedge that scrape just over the edge of the wall eviscerating any intruders. The “forest” surrounding the city is littered with trees cut at 45 degree angles (some still on fire), craters, giant spider husks, etc.