The Verenian Watchers
Chuul are amphibious aberrations created by the aboleths to build and enforce their rule. They serve the Infinite Empire as faithful, mindless worker drones. They live to enact the will of the aboleths that created them, and should there be none in the vicinity, they strive to complete the last instructions they were given endlessly until another aboleth arrives to give them a new command.
Physiology and Abilities
Chuul are terrifying opponents because of the unique advantages that they have in combat. Their chitinous shells alone protect them from direct physical harm, making them difficult to take down by any but skilled combatants. Couple that with their immense size and overpowering pincer claws, they very literally overwhelm their opponents, physically holding them in their claws to keep them from retaliating in combat, and then pulling them in close to paralyze them with a potent venom that is secreted through facial tentacles.
Chuul are also gifted with the ability to detect magic within a limited radius, meaning that anyone who dares to approach them with magical items are unable to get the drop on them.
The most effective strategy for defeating chuul is to keep them at bay with powerful ranged attacks and spells, as their powers only truly aid them in close-quarters physical combat. Advantages of terrain make defeating the beasts much easier.