Originally from Charos, Brain collectors; or "Neh-Thalggu" are powerful magical creatures who collect the brains of other intelligent beings. They are usually found in the Underdark.
Each specimen of this hideous race has a bright green, bloated, and oily body. with eight sharp crab-like pincer leg appendages that allow it to scuttle about. Set in its bulbous head, Neh-Thalggu have over a dozen bright yellow visual sensors that serve as its eyes, and a razor sharp, tooth-filled maw. The head and body also have a number of distinctive clear blister-like membranes; each one housing the brain of another intelligent creature. Usually there are are twelve blisters, but some sages believe some brain-collectors possess many more.
Neh-Thalggu only communicate using their own tongue, but can comprehend the languages known by any creatures whose brains they’ve consumed.
Combat
The brain collector’s method of attack is a powerful bite with its razor-toothed jaws. Each brain collector can also cast spells, depending on how many brains it has collected. Each transplanted brain can hold a single wizard spell, no higher than 3rd level.
A brain collector can attack with its bite or with a single spell in a given round. Although the nature of its intelligence is unfathomable, brain collectors display a considerable tactical cunning in combat; they will use their available spells to the best possible effect.
A brain collector takes great care as it fights, to avoid doing damage to the cranium of its opponent. As its name suggests, the brains of sapient foes are very precious, indeed.
Habitat/Society
Though brain collectors have a completely alien psychology, “chaotic neutral” is the alignment that best describes them. The Neh-Thalggu do not have hostile intentions as such; rather, they do not seem to regard humans or or other humanoids as people.
When a brain collector reaches the Prime Material Plane, it immediately begins acquiring as many brains as it can, as quickly as possible. Each collector can store up to 12 brains at any one time. When these creatures slay humans, demi humans, or humanoids, they carefully cut away the top of the head with surgical tools to expose the brain, and then swallow it. The swallowed brain then moves into one of several pockets within the brain collector’s own head, forming a distinctive lump. For each brain collected, the creature gains the ability to cast one wizard spell of 1st to 3rd level once per day.
When a Neh-Thalggu has collected its 12 brains, it immediately seeks to return to its home. One theory holds that with 12 collected brains, these monsters can, in certain locations, re-open the link to their native plane. Fortunately, few 12-brain Neh-Thalggu have been encountered; since they can collect no more brains, they are more eager to move along than to engage opponents.
