The Grinder is the colloquial name for the body of water that separates Lanad i'Sarois and the Sea of Egaby in the north from Rannas i'Drasoin in the south. It is called The Grinder because sailors say it grinds ships up like meat.
This area of ocean, which straddles Ardrana's equator, is dotted with rocky outcroppings, both above and below the surface. Some of these are the size of small islands -- rumors say that there are even creatures that live on these islands -- but most are the size of large boulders. What's more, these rocks move -- some continually, others periodically -- and navigating them is about as great a hazard as an ocean-going vessel might encounter. There is also a large population of sahuagin in the area. These creatures prey upon ships, whether caught on the rocks or simply waiting on one side or the other for an opening to sail through.
Needless to say, sailing through this region is avoided at all costs. Those who must sail through it either go as far to one side or the other as possible, skirting the coasts of the central Ardann i'Parastha, or hire a guide who knows the patterns of the moving islands. Such guides charge a high price for their services, and even then there's no guarantee the ship will come out undamaged.
The origin of The Grinder is a matter of debate among sages. Some say that it was born of the same cataclysm that caused much of the eastern Rannas to sink beneath the ocean in ages past, and others say it is the remains of a land bridge that once connected the Rannas to the Lanad. Some even claim that there are one or more nexuses that infuse magic into the rocks themselves. Very few are willing to brave its perils to uncover The Grinder's secrets.