Way in the Deep Down Below, a clan of degenerate Halflings worship Aboath, the God of Filth. The disgusting River of Slime is a sacred spot where these Filthlings perform their disgusting baptismals. What connection these creatures may or may not have with the Sludge Dwarves remains to be seen.
Drawn freehand on board with illustration pens. I'm not sure I like the "outline" I put around the map walls.