The Ancythrian Sea is a large inland saltwater sea in Santharia, nestled between the Enthronian Province to the South and East, and the Province of Vardýnn to the North and West. From north to south the sea measures around 420 strals and has around 260 strals of maximum width measured from east to west. In opposition to its name, which comes from the Styrásh meaning “Silent Sea” (actually the original name was "ancí'thyrón", the Ancythrian Sea is not silent in the least, though it might have been calm in ancient days. Today it is the home to many undersea creatures, such as the cáeh'fish and khendochar, and home exclusively to the Ancythrian shark. The sea is more than abundant in fish, and the local fishermen are sure to take advantage of that.

The Ancythrian Sea is also a major trade route between the Enthronian cities, having a port at Cavthan to the east, and at Elsreth to the west. Aside from that the sea is home to the Enclave of Alvang, an isle shrouded in mystery, as it was the site of a great battle, also known as the “Witchking’s Night”. Many an adventurer is said to have sailed into the heart of the sea to discover its secrets, and has not returned. Because of this, the townsfolk of Cavthan for example have taken to calling the sea by fell names such as the "Devil Sea", or the "Witchking's Waters".