In the Demon Spawn War(89 GE - 269 GE), the Covenant constructed seven fortresses within and surrounding the Ebonmurk Sea. Darkwatch, later known as Eclavfryn, defended against aquatic demons and hostile natives. These natives were peoples concerned solely with survival, preying upon the weak and wounded, and uninterested in aiding the demons or the Covenant. Three of the greatest threats were the Lacedon emerging from the Hall of Hades, large bands of Scrag, and often the most perilous of all, attacks by teams of aboleth. The aboleth, Athena would write, are constructing an empire from slaves, a dreadful people that even she sees no value in preserving once the demons have been vanquished. On the opposite side of Darkwatch, patrols traveled northward, purging the expansive caverns that would later become the Great Tradeway, destroying the seemingly ceaseless spawn of Zuggtmoy.
In 831 HE, Darkwatch was secured and resettled by colonists hailing from Filion'lyr. Renamed with the Drow term Eclavfryn, it emerged as the initial prominent port of the Ebonmurk in several millennia.