BirdieMaps has created this spectacular sewer battle map which would work perfectly beneath Ptolus. They created it with a thief hideout in mind, but this could easily be a ratman nest for your City by the Spire Campaign. Download the large version of the map completely free. Consider supporting BirdieMaps on Patreon.
Huge Sewer System Map with Thieves Settlement under Ptolus
About the Author: Narrator
My name is Ellis Benus and I'm a Web Developer by day, and an avid Dungeons & Dragons / Pathfinder player by night, and sometimes day too. I've launched this website because I love the Ptolus Campaign Setting by Monte Cook and found the Book simply too limiting to really use the system. Checkout my other sites: https://EllisBenus.com & https://d20.pub/