Sador is the desert neighbor to the Land. The Two are divided by Blacklands which prevents much travel between them except by sea.
We first learn of Sador in the 3rd book; Ashling. While Elspeth is at a Rebel Meeting in Sutrium a Sadorian representative reccomends a journey to Sador to solve a conflict.
The people of Sador are descended from the Gadfians. They are nomads and they travel their desert land in Kar-a-vans. Their religous beliefs revolve around their Earth Godess. They built an EarthTemple into a cliff-face near their main port.