New D&D setting – the Endless Sea

Ok, kind of a cheesy name but it’s not a definite set yet. Here’s what happened –

I was reading an article on Wikipedia about Nan Madol, a sunken city in Micronesia that used to be a capital, and then I got thinking about other sunken cities, and then I made a list of their names.
And then I started thinking about a sunken sea or sea-based game and it all went from there. So, here’s a blog post to save some notes for future reference.

The Endless Sea is a big place, and seemingly always changing. Maybe the local gods are whimsical, maybe they’re just petty.
The various races that make the place their home seem to have stumbled on it by accident and possibly arrived from entirely different worlds altogether, falling through storms or navigating through thick mist and finding themselves atop the faintly shining waves.

The Sea changes, islands appear, move or disappear with no underlying pattern, but somehow a few points remain unchanged, and so the largest settlements are found there.
In the Common cant, the word Burh is used to describe them – places of safety built around some form of a keep. None are much bigger than the others, and they administer their own affairs for the most part. Temporary alliances may be formed, but like the ever-changing sea, they don’t last too long.

One peculiar quality of the Endless Sea is its abundance of Aetherium Salts in the waters. By extracting Aetherium, magical and wondrous items of all kinds can be constructed, medicinal potions brewed, and, some say, escaped from the Endless Sea becomes possible.

There is one fixed point in the entire Endless Sea – the Oud. A great black tower with impossibly smooth walls, it disappears into the sky in the day and the stars at night. Compasses point towards it, sea creatures stay away from it, and people venerate it as the home of the local gods.
The only other structures as impossible are the ruins of the Vineta. Sometimes their artefacts are found in fishing nets or buried in the sands after high tide, or even on briefly appearing islands. The strangest thing about the lost culture is their lack of tools used in sea travel, and that none of their translated inscriptions makes the slightest mention of the Endless Sea.

That’s all I’ve really got so far. I have a list of races in mind – Humans, Changelings, Genasi, Gnomes, Minotaurs, Shifters, Tabaxi, Tieflings, Tortles, Triton, maybe Goblins, Kobolds and Kenku.

Names of some of the Burh –

Ravenser Odd
Nan Madol
Rungholt
Reimerswaal
Long Sault
Saaftinge
Llys Helig
Sarkel