Merfolk

Merfolk are aquatic humanoids that have the upper body, arms, and head of a fair-featured human from the waist up and instead of legs it has a fish-like tail from the hips down. Males are called "Mermen", while females are called "Mermaids". Their humanoid features are fey-like, more similar to elves than humans. Merfolk are capable of interacting with surface folk, as they can survive outside of the water. They do so rarely, however, as they cannot walk on land.

Society
Merfolk live in cities and isolated settlements within shallow seas and coral reefs, where protection and food is abundant. They train aquatic animals to serve as their guardians, similar to the way humans train dogs and horses. Merfolk's only natural enemy is the Sahuagin. (Sahuagin are a fish-like, monstrous-humanoid species that live in oceans, seas, underground lakes, and underwater caves.)

Mermaid
Classic mermaids are fey-like creatures, loving for the most part and a few with a dangerous disposition. Some Females who lost their mates would entice sailors with their beautiful singing voices to steer their ships into dangerous reefs or to jump into the water where the mermaids would then drown the hapless man. Mermaids of this sort are often referred to as sirens.

Religon
Merfolk worship the god Eadro.