Merfolk are aquatic humanoids that live throughout the waters of many D&D worlds. They hold to neutrality on most issues, neither championing causes of Good, nor perusing the dark secrets of Evil. They may be allies, if their needs fit the needs of the party, or they may be rivals if they oppose the party's actions.
Merfolk have the upper body of a human, and the lower body of a fish. They can breathe air and water equally well, and can be found lounging on beaches and on ragged rocky coastlines.
Merfolk first appeared in the OD&D White Box under the name "Mermen." There, they were described as similar to Berserkers, armed with tirdents and darts, but they fought at a penalty on land, and had natural armor.