The northern of the pair of islands that are Tideborn lands, the southern with City of Raging Tides being called Barrier Island. The Island of Broken Dreams to the west was originally intended to be south of Barrier Island, as this quest book indicates: Book of Broken Dreams only usable by level 6-23: Much of the Goshiki Quest Chain takes place here, of course, including killing the second Tideborn Traitor and the difficult Chrono Core fish leviathan