City-state in Mosaî nearest to the one of the portals. Along with the “twin cities” of Aghbalu and Bukkus, this economically depressed region is known as the border between North and South Mosaî.

Prior to the portal's “arrival” in III:1108, Usem was very poor and somewhat lawless. The leaders hoped that the new trade from those using the portal would bring some kind of prosperity – so they were the only people in Mosaî to welcome the foreigners. However, after ten years, this economic boon has failed to materialize and Usem has grown impatient and somewhat paranoid.