Kuo-toa

Kuo-toa are a debased monstrous humanoid fish-like race, in the Dungeons & Dragons role-playing game, that dwell in the Underdark. They were created by Gary Gygax, one of the creators of role-playing games, and first appeared in dungeon module D2 - Shrine of the Kuo-Toa.

Description
Kuo-toa have human-like bodies and fish-like heads.

Society
Kuo-toa often raid seaside settlements for human victims. They worship the goddess Blibdoolpoolp.

Kuo-toa in the Forgotten Realms
In the Forgotten Realms campaign setting kuo-toans maintain friendly relations with drow, their Underdark neighbours. Blibdoolpoolp is the focus of the kuo-toans' lives, and even has her own monstrous, deformed kuo-toa breed - the giant kuo-toa leviathan.

Kuo-toa in Greyhawk
In the World of Greyhawk campaign setting, kuo-toa settlements are known to exist in the Underdark, near the Vault of the Drow beneath the Hellfurnaces.