Originally from Charos, Grell are fearsome predators which dwell in the Underdark and work closely with the race of Illithids.

With their bulbous head-body and trailing tentacles, Grell resemble bloated flying jellyfish about five feet in diameter. Their gray-green mass is covered in folds and wrinkles and appears like nothing so much as an enormous brain with a hard bony beak.

Below its body trail ten pinkish, purple tentacles with retractable barbs which can inject a paralytic toxin. The creatures have no eyes, instead perceiving the world via sound waves and electrical impulses through their skin.

Most of these creatures are solitary, dwelling in underground ruins or caverns and hunting their prey by dropping down, paralyzing them, and then carrying them off. On occasion, Grell will come together to form large colonies.

These colonies are led by “Philosophers;” venerable Grell of advanced age, size, and intelligence who possess special magical talents. Grell lairs often contain underground pens where captive humanoids and animals are kept as a food source.

Despite being highly intelligent and possessing an alien tradition of magic, the Grell have little in the way of society or culture. They do not build any structures save for the occasional low wall or shelf in their lairs, made from “Grell-Crystal”, a substance grown from the creatures powdery secretions mixed with water. These creatures often craft strange magical weapons to aid in their hunts. The most commonly-used Grell weapon is the "Lightning Lance," a wand-like staff which stores powerful electric charges.

Grell concern themselves entirely with the consumption of living flesh, and will not treat with other species unless forced. Even then, the more powerful party is always seen as a potential meal.

Grell are known to have only one ally; the race of Mind-flayers. The two species have worked together for thousands of years.