Thraw is the only kingdom in the Grand Alliance that is composed of a single race; Raptorians, only their own species is allowed inland and all trade is performed in the single large port. Their peaceful nature means inclusion in the Grand Alliance is important for their safety, fortunately they are the only beings capable of crafting a unique magical item (Kor Stones) which is sought after by almost all magical adventurers.
Before the Raptorians became a single nation, they were half a dozen fighting tribes, until a one of their shamans received a vision of what they could be. Over the next forty years this shaman shared his vision, literally, with the other tribes, peace was slow but when it finally arrived it was glorious.
The island itself is raised far above the ocean, with just one small mile long section low enough for outside trade, the height not only explains why only Raptorians were able to reach the island in the first place, but also keeps out most unwanted visitors.