THELIDU (Brain Demons)
Armor Class: 5
Hit Dice: 4+3
Attacks: 2 Claws (1d6 each), Tentacles (1d4)
Saving Throw: 12
Special: Mental powers, Brain extraction
Challenge Level/XP: 8/800 XP
The Thelidu (the term is both singular and plural) are a hateful species of conquerors from Outside who use use weird devices to travel to other worlds in search of slaves and resources. Possessing scaly, rubbery, vaguely humanoid bodies, the Thelidu have octopus-like heads and faces that are masses of feelers. Gelatinous green in color, these monstrosities are worshipped as near-gods on countless worlds -- and feared on countless more. Obsessed with the purity of their own species, the Thelidu regularly engage in internecine wars to exterminate the "unfit" in their midst, an activity they enjoy even more than conquering and enslaving other species. This trait is one of the few things that have saved worlds from Thelidu conquest, as these alien beings are relentless in their campaigns of domination.
Thelidu are masters of the mind, which has earned them the sobriquet "brain demons," even though they are not in fact demons of any kind and indeed view demons are just another species to be conquered. All Thelidu are capable of using several abilities that mimic the effects of arcane spells: charm monster, charm person, clairaudience, clairvoyance, ESP, levitate, and suggestion. In addition, a successful melee hit on a single target with both claws and tentacles results in death in 1d6 rounds, as the Thelidu cracks open the victim's skull and extracts its brain, resulting in immediate death.
The extracted brain is then added to cerebral devices known as Brain Complexes, of which every Thelidu band possesses at least one. The precise purpose of the Brain Complexes is unknown but some sages surmise that they create and/or power many of the other queer devices the Thelidu carry with them as they scour the cosmos for worlds to conquer. Whatever the truth of the matter, the appearance of these beings on any world ought to be a cause for alarm and swift retaliation, lest they gain a foothold from which they can never be dislodged.