Akuparan Cities
by Marc SaindonSo nothing inventive here, but simply adding a more seafaring network of city-states in the Sea of Dread who rely on pacts with Giant Chukwa Turtles for protection and continued existence. Their mobility explains why they weren't on the map before.
The Akuparans' main antagonists are the Reavers - Pirates from Jaibul - who raid and enslave them. Events from X4 - Masters of the Desert Nomads, might have them flee towards Ierendi (albeit slowly).
For PCs, it can provide a mobile port of call, with their moving faster during adventures, while an Akuparan City might follow them during the downtime between adventures. One idea might be that over-population requires new lands to settle, and the Isle of Dread module could be scouted.
(Image from: https://www.deviantart.com/blink4art/art/Fantasy-Turtle-Day-378234401)