The Dread Sea lies a long way beyond the safe and cosy underground Jarldoms of the Dwarfs, beyond the furthest borders of the many realms that make up the great empire of Men, beyond the stinking pits of the loathsome and argumentative Goblins and Orcs, and beyond, even, the ancient and mysterious lands of the Elves.
Once, the thousands of islands the make up the Archipelago of the Utterly Damned were occupied by the various races of the world, indeed it appears that the races even lived side by side in harmony with each other. Legend tells of a truly cosmopolitan city, the heart of a thriving multiracial empire, long since swallowed up by the waves. Or a giant squid. Or possibly a sea dragon. What’s for sure is that the souls of those who lived there never made it to Valhalla, nor The Great Gold Mountain, nor The Place With Endless Chicken and Beer, or any other of those peoples’ afterlives.
This is known, because they are still there, in the Dread Sea. Some on great hulking, fearsome blackened ships, sailing for ever across the Undead seas, sinking any vessel they find and feasting on the flesh of the living, others marching in armies across the sea bed in an endless campaign to invade the prosperous lands of the modern races, many thousands more slowly dragging themselves around the islands of the archipelago, hoping to bump into any living soul foolish enough to have entered this cursed place, to steal their life, their body, to return themselves to life…
…of course, no one would be stupid enough to enter such a place. Would they?
The thing about the Dread Seas is, of course, that the long lost civilisation which has left a somewhat problematic infestation of the undead covering every inch of the thousands of square miles the area covers also left behind…everything. Gold. Jewels. Learning. The secret, somewhere perhaps, of their peaceful and harmonious existence. Also Gold.
And where there be Gold … tharr be pirates!
Of course, there are easier pickings sailing along the edges of the Dread Sea as well, and sometimes even through them, if brave captains have been paid a high enough bounty to risk saving time by crossing them, and the Pirates of the Undead Seas occasionally supplement their treasures and adventuring with attacks on the merchant fleets of the races of the world. This is what makes them pirates to their own governments and wanted to a man (/dwarf/elf etc).