Roiling Abyss
The Roiling Abyss is a body of water amidst the open seas of the West. Though not located near any major landmasses (the closest inhabited islands being Port Foul and the Pigeon Islands to the west and Anchorstone to the east), it sits alongside the powerful sea currents crossing the empty open seas to link the populous lands of the Ocean Sea to those of the southwestern seas.
The waters of the West’s open seas are deep, but the Abyss is deeper still, a huge black gash descending into darkness beyond the reach of the Unconquered Sun’s light. At such depths, divers might happen upon Giant Squid and fat Anglerfish the size of sharks, and below that horrors from the Primordial Era that have never known light or colour...
The storms of the Abyss are strong and constant, endless thunder and crashing waves circling through the waters in an oblong spiral. Only the most foolhardy sailors (or those equipped with magics and protective artifice) would brave these storms of their own volition, but there is some temptation: the trade currents run strongest near the edges of the Abyss, and a vessel which takes the risks of skirting the Abyss can take a significant lead over one which keeps conservative distance.
Pirates also value the currents for the fat merchantmen they carry in, but their vessels face as much trouble with the storms as any other, so they tend to prey on vessels further out, making the storm risk appeal to traders who fear they might fall victim to corsairs. A few pirate crews, usually who have mastered some form of supernatural protection, use the Abyss itself as cover for their ships, so they might swoop quickly from the stormfront and take their prizes by surprise, but given the dangers of this tactic it is quite rare, more likely woven in an inventive tale at a Free Port tavern than seen in practice. More likely a pirate ship, faced with pursuit from one of the West’s great navies, might take the risk of the Abyss over certain death on capture and attempt to flee directly through the Abyss. Also, as merchant ships attempt flight and pirates launch pursuit, strong winds and currents can pull ships into the Abyss, where they near-inevitably meet their doom.
Alas for those on the nearby waters, the storms which roil in the Abyss do not stay confined there, a typhoon or thunderstorm sometimes spinning free of the greater storm to twist its way across the open ocean before eventually calming. Islanders dwelling nearby oft have very close eyes for shifts in weather, so they might bring in their boats and lash down their possessions before a tempest closes on their homes.
Due to its depths, the Abyss is not thought to be home to any islands, though charting its extent in search of them would be difficult, and some wild stories tell of hidden pirate bases or treasure-filled ziggurat-tombs of Anathema whose upper levels pierce the surface. In truth, there is only one island within the roiling storms, and it is uninhabited and uninhabitable, located within a small sphere of calm at the eye of the massive storm: the Starfall Stone.