The Thestron Sea lies to the north of mainland Altandor, filling the space between it and the Xaril Coast. The waves are choppy on a good day and deadly on a bad one, with storms liable to send jets of icy water onto the deck of any ship brave or foolish enough to brave these waters. Most days are cloudy with a stiff wind, and many of the remainder are stormy. A clear sky with favorable weather is a rare for anyone living on the northern coastline, or on the Sukrehl or Mokame Islands. During the winter, the water become choked with icebergs, making passage all but impossible.
The Thestron Sea is largely devoid of civilization, with the exception of the kobold tribes living on the Sukrehl Islands. The Ethiviran make use of enchanted warming stones to brave the frigid waters in search of prey, with the limited number of stones being handed out to only the most skilled hunters and swimmers.