The kuo-toa, distant cousins to the modern sahuagin of the eastern sea, and slaves of the ancient Draakin, survive in small clans amongst the ruins and natural caves that dot the coasts of Pterra. While the kuo-toa people are not inherently evil, their dominant religion is. They worship an ancient evil race of creatures that were said to have risen from the depths of the ocean, or from another realm (even the kuo-toa are unclear about this). These beings were said to have brought about the destruction of the old Draakin empire. Even the sahuagin themselves whisper about these powerful creatures, but see it as a crime against their god to speak the name of this powerful race.
The kuo-toa fight regularly with the other inhabitants of Pterra, raiding settlements for slaves to sacrifice to their evil "gods."
DM Secret: The powerful race is, of course, the aboleths. Some of the sacrifices are not killed, but rather transformed into the Skum, the traditional slaves of the aboleths. The ancient aboleth empire existed long before the Draakin, both above ground and below, but when the world's climate changed the aboleths migrated deep into the ocean. When they returned, they were enraged at the Draakin people, and manipulated various forces to bring about the destruction of their empire. The kuo-toa were easily manipulated to rise up against the Draakin due to their enslavement, and the aboleths decided to keep the race alive after the fall of the Draakin. If one delves into the oldest of the Draakin ruins, and deep underground, they might find some of the rare signs of some very alien and decidedly non-Draakin culture, such as statues, artifacts, and the like.