Kuo-Toa

Kuo-toa are degenerate fishlike humanoids that once inhabited the shores and islands of the surface world. Long ago humans and their ilk drove the kuo-toa underground, where they dwell in madness and everlasting night. Kuo-toa can no longer abide daylight.

Mad Slaves

At the height of the illithid empire, the mind flayers captured kuo-toa by the thousands and forced them into bondage. The kuo-toa were simple creatures, never meant to endure the oppressive mental force the illithids unleashed against them. By the time the mind flayers abandoned them, the prolonged psychic subjugation endured by the kuo-toa had driven them mad.
Their minds shattered beyond repair, the kuo-toa adopted a religious fervor, inventing gods to protect them against threats. Most notable of these threats are the drow, which have slain the kuo-toa on sight since the days when the two races first met.

Worship

Kuo-toa worship gods of their own insane creation, but if enough kuo-toa believe that a god is real, the energy of their collective subconscious can cause that god to manifest as a physical entity. The form a kuo-toa god takes depends on the inspiration for its divine image, and is usually random or nonsensical.
One of the most revered gods of the kuo-toa is Blibdoolpoolp the Sea Mother, who takes the form of a female human with a crawfish head, a crawfish’s claws, and an articulated shell covering her shoulders. Blibdoolpoolp was likely invented by a kuo-toa that improved on a broken human statue by adding the limbs and head of a crustacean. In sudden awe of its handiwork, it then named the resulting form a god.
Kuo-toa that cross paths with an aboleth often find themselves worshiping it as a god, their madness blinding them to the fact that the aboleth is merely using them for its own nefarious ends. There is also a large, growing cult of kuo-toa who worship the demon Dagon.

Theocratic Rulers

Kuo-toa archpriests are surrounded by fanatical devotees of their faith. The archpriest of a kuo-toa domain demands that all its subjects worship a specific god. An archpriest’s mad belief in its god is so fervent that it manifests the powers of a high cleric. The archpriest can also bestow spells to devout underlings called whips. One or more of these whips are also the archpriest’s children, and their primary role in kuo-toan society is to fight to the death to claim the throne when the archpriest dies. If a whip displeases the archpriest, the archpriest can strip it of its spellcasting ability, if not its life.
The archpriest’s decrees are enforced by monitors, devout kuo-toa that act as the archpriest’s eyes and ears. Monitors are deadly hand-to-hand combatants, and lesser kuo-toa live in fear of them.