The Gray Tide, led by Prince Kel. His holdings are named after the dread magical mist that lingers over the waters surrounding Lastpoint Island.
Source: ECG
Changelings have always been viewed with suspicion by most of the people of Khorvaire -- and occasionally that fear has boiled over into something worse. Thirteen hundred years ago, the lords of the nations now known as Karrnath, Cyre, and Thrane began a campaign of extermination against the changeling race. Many changelings fled to Breland or Aundair, hiding among humanity. But one among them was not satisfied with survival. This changeling was named Kel, and he had a vision of a changeling homeland: a realm on the edge of the world, where changelings could live away from the fearful scrutiny of humanity. He traveled the land, speaking to family after family, and slowly an exodus began -- a journey that ended on the island of Lastpoint. There, staring into the disturbing wall of the Gray Tide, Kel declared that they had found their home.
No outsider knows the full size of the Gray Tide principality. Some estimates say that there are over fifty thousand changelings in the Lhazaar Principalities, though it is impossible to know for certain. Changelings have spread out across the islands, and many of the brothels and theaters in the Principalities are run by changelings. Lastpoint changelings also serve as guides, interpreters, and mediators, serving as hirelings on ships of other princes. Some Lhazaarites fear that the changelings have spread far deeper into Lhazaar society than anyone knows. But most are willing to see the changelings as brothers on the sea, and they are more accepted in this region than anywhere else in Khorvaire.
The Gray Tide principality is thought to have four ships, and common belief holds that it does participate in piracy. However, a host of rumors has circulated about the principality. Some say that the changelings can enter the Gray Tide without danger, and that they have a fleet hidden within it. Other tales claim that the changelings have developed ships that can shift appearance, so that their acts of piracy are blamed on others. The truth of these tales is in the hands of the DM.
Source: Dragonshard Part 2
The Gray Tide Principality, in addition to being an unexplained feature of the sea beyond Lastpoint Island, is led by another changeling, Prince Kel (N male changeling rogue 6). He dreams of establishing a homeland for the changeling race and has succeeded in drawing a significant population of changelings—mostly followers of the reality seeker philosophy (see page 24) trying to create a perfect community. The Gray Tide is located on and around Lastpoint, though rumors say that it has a fleet hidden in the tendrils of mist from which it takes its name
Source: Player's Guide to Eberron
Founded three hundred years before Galifar, the Gray Tide principality was founded by a changeling named Kel. Seeking refuge from flaring anti-changeling resentment that was sweeping the nations that would become Karrnath, Cyre, and Thrane, Kel gathered changelings from all over in exodus to the isle of Lastpoint, an isle half covered by mysterious mists known as the Gray Tide.
Kel bravely led the refugees into the mists of the Gray Tide. The changelings were accepted rather than rejected by the mists and founded the city of Sanctuary as a permanent refuge from the suspicions of Khorvaire. One unfortunate noble sent warships to put an end to the “changeling threat”, but these ships never returned from the mists. To this day the superstitious and the wise steer clear of the mists, and many stories of missing ships involve them getting lost in the Gray Tide.
The true scope and size of the Gray Tide’s fleet is a mystery. Ships rarely fly the Gray Tide’s flag openly, preferring to disguise and even integrate themselves into other fleets. Adventurers in any of the dockside taverns may hear a particularly paranoid sailor spreading rumors that the Gray Tide has slowly conquered the Principalities by replacing its key captains and crews with changelings. Other rumors say the Gray Tide sails on enormous living ships, mimics capable of shapeshifting to disguise themselves as friendly ships. One tale describes a ship covered in kelp that pretended to be a shipwreck before animating and attacking.