Thraum fortress, also known as Windstone and Saltstone, was a Dwarven fortress located in the Waterlond ocean, close to the Labyrinth Winds and Frostfell. Its location northwest of Silur made it easily reachable from the Dwarven Kromlagen colonies and for ships in difficulty near the Labyrinth Winds.

History

Thraum was planned and built by General Graumfern Frostbeard. Its location was chosen for easy defensibility. It was also supposed to be recluse, a place where secrets would be kept. The construction itself was very difficult: the island on which the fortress was built had cliffs on all its sides and the water was very choppy. A cave opening on the ocean was widened out and secured against collapse so that ships could actually dock in safety. Then, the entire cliff face - which degraded relatively quickly otherwise, crashing into the ocean - had to be strengthened and in part filled in with mortar. The fortress proper, which was built above ground to scorn upon the ocean and look impressive, was then constructed out of granite that had to be imported on heavy cargo ships from Kromlagen. During the whole construction, which took multiple decades, seven ships were lost.

Initially, it was a highly secure base of the navy. It was used to patrol the waters north of Silur and to help ships in difficulty near the Labyrinth Winds. It wasn't a very profitable enterprise, however, and it was relatively impractical for warships to use Thraum rather than Kromlagen ports as harbor. The underground port was of a relatively small size, especially for the infrastructure above - much area was necessary for supply ships and couldn't be used for warships. The terrible weather, featuring strong winds, bad sea, and very cool temperatures, wasn't very good for sailor morale.

In 17'249, the base was restructured and used as a prison instead. Its very recluse location made escape completely impossible, and the vast dark halls could easily be restructured into solid cells. Mainly dwarven criminals were imprisoned here, usually for a century or two. The fortress was also still used as a base for the navy.