The Restless League is a group of pirates based out of a hideout near Stros M'Kai, led by a man named Basil. They have a secret connection to the Crowns, formed when Iszara joined the League. They use raids and piracy to weaken the Empire, but their ultimate goal is to restore Prince A'tor, so that he may lead them to victory.
The League gained the attention of Prince A'tor when Iszara joined, just after the death of Thassad II. The Prince kept his affiliation with the League quiet due to their poor reputation as pirates. To aid the Crowns, they fought the Forebears and Empire discreetly. During the Battle of Stros M'Kai, however, they were forced to stay back and watch the defeat of their allies. They managed to secure the soul gem containing the soul of A'tor, who fell in the battle.
Iszara and other members of the Restless League planned to restore the Prince using the soul gem. Iszara decided to steal the gem and take the matter into her own hands. A month or two later, the League blew up Richton's flagship and laid low until their attack on Brennan's ship. Cyrus manages to contact the League and learn of these events. He returns to the hideout after rescuing Iszara, and at this point makes the League's cause his own. Later, Cyrus attempts to restore A'tor but obtains the soul sword instead. He rallies the League to fight against the Empire while he razes the Palace.