Nightmares of the Last War
llithids have a basically humanoid body, but their head is octopus-like. They have four tentacles around a lamprey-like mouth, and require the brains of sentient creatures as part of their diet. An illithid who snares a living creature in all four of its tentacles can extract and devour its living brain. Their eyes are pale white, and they can see perfectly well in both darkness and light. Their sense of hearing is slightly poorer than a human’s; they have difficulty distinguishing between several sounds mixed together. Their skin is purplish blue to gray-green and covered in mucus, and is very sensitive to sunlight. Though sunlight does not actually harm them, they loathe it with incredible ferocity.
One of the most feared powers is the dreaded Mind Blast, where the illithid emits a cone-shaped psionic shockwave with its mind in order to incapacitate any creature for a short amount of time. Illithids also have other psionic powers, generally telepathic in nature, although their exact effects vary. Other powers include a defensive psionic shield and powers of psionic domination for controlling the minds of others.
The mind flayers are the chief servants of the daelkyr. The elder brains may be daelkyr creations, or they may actually be spiritual and physical extensions of the daelkyr. In either case, the elder brains form the backbone of the telepathic network that links the daelkyr together and allows them to monitor their servants.