Precis: Industrial hell through a Gothic lens.
Conspectus: An island that is home to a foul, polluted factory city of the same name; Nasos is ruled by a council of its wealthiest citizens, but the middle and lower-classes frequently live under states of anarchy; rotting compost, raw sewage, and huge mounds of trash choke the streets; everything is coated with a thick layer of industrial grime; the wealthy members of Nasosian society throw frequent masquerade balls; the upper-classes fear the diseases and contagions that run rampant among the lower orders; the sewers of Nasos are home to dire rats and otyughs.
Commentary: Nasos is another excellent place to add a modern steampunk-horror vibe. There's definitely a lot of potential for demonic factory machine run amok here. Also, the exclusive masquerade balls coupled with the upper-class's fear of disease is perfect for riffing on Poe's "Masque of the Red Death." (Is there a finer example of horror-fantasy? I think not.)