Ysian

The lost continent of Ys was sunk by the arrogance of man, precipitating the Apocalypse of the Third World, and ending the Time of Dragons. Some mortals held on and used dragonsblood and dark magic to sustain themselves, and became the merrow, a race twisted by millenia of hatred towards the surface, the dragons, and other mortals, as well as centuries of torture by the demons they unleashed. Now unrecognizable and deeply Evil, they have secretly spread their influence over the oceans, claiming that one day they will have their vengeance, though their constant internecine struggle has kept them from ever actually mounting an assault on the surface. In the Sixth World, their power wanes even further as beastfolk such as the kuo-toa and locathah spread. Still, other aquatic peoples such as the sahuagin often owe them fealty, and they have become thoroughly infiltrated by the alghollthu.