For what it’s worth (not much), I built more into the background of Cauldron and Sasserine about their history as “secret colonies” of the Hold of Sea Princes (to explain why they aren’t on most maps), with more colonial Caribbean features. The economy and society are built on slavery growing primarily sugarcane.
So slavery wasn’t a hidden secret under the city, but in the open once you climb down from Cauldron. (I also had free farmers growing coffee on the mountainside.) The group who attack the inn between Cauldron and Sasserine I had be Maroons - escaped slaves living beyond the reach of the law - raising money for their rebel campaign to overthrow Cauldron. The PC’s were mostly from outside and became associates with the Maroons - one PC was reincarnated by their leader and the PC’s traded with them, compared notes, and gave them spare weapons. Didn’t finish the campaign for real life reasons, but it would have been interesting to see where it went - I plan themes and setting, not what will happen.
I’m thinking of adapting the sea trip from Savage Tide (Wake of the Sea Wyvern) to combine with some concepts from “Ghosts of Saltmarsh” and some Dungeon scenarios to have a theme about New World exploration and colonization, including some lost Great Kingdom colonies.
The real world truth that Scandinavians colonized Greenland but forgot a place they once traded with and had church records for existed is fascinating to me. So a D&D version of “forgotten colony” is something I want to delve into. Roanoke only much more so.
