Rust is a floating trading city/port built out of scrap metal. It is located a short distance away (about a day's journey) from Shoggoth, and about a week's journey from the Nealend Atoll. Similar to Gray Smoke in many respects, its inhabitants are mainly profiteering businessmen and traders governed by a union known as the Syndicate.
Dark metal walls form the outside of the city. Inside, there is a large number of docks and canals which form a sort of artificial atoll.
The city itself can be divided into 3 layers. The bottom layer is a series of heavy metal pilings grounded on the ocean floor, which maintains the structure of the city. The middle layer is composed of floating platforms and ballasts which are built around the vertical struts of the base layer. This forms a foundation which allows the rest of the city to rise and sink with the ocean while still remaining in place. The top layer is a bazaar of shops, docks, warehouses and businesses which are built and stacked haphazardly on top of each other, reaching approximately 3 stories tall in places.