Caer Draenok
From The Thalassan Sphere
Summary
Caer Draenok was an ancient dwarven civilization about which almost nothing is known. It was discovered by builders of the Free City of Vyzantium expanding that city in 4922 FYA and was used largely as cover during the Rain of Filth.
After the founding of the Sunspire, the burghers of Vyz made a concentrated effort to bring dwarves to the island to populate Caer Draenok and founded the Deep City of Undervyz for their purposes on the footprint of Caer Draenok.