Theumea (pronounced thew-MAY-ah) is an island that lies between the Chaska Sea and the Sea of Ersas, one of the largest and southernmost of the Ten Thousand Islands. The sole major settlement on the island, Odarta, is controlled by Eretrebus. The city lies in the shadow of Mount Odarta, a volcanic peak that accounts for much of the island's surface.
Theumea is a rather rocky island, but its largely ashy soil means that vegetation has an easy time growing on the slopes of the volcano. Still, little of the island is used for agriculture, mostly limited to some small farms on the outskirts of Odarta.