Illuminati
From Warhammer 40k
The Illuminati are a subset of Humanity, defined by having not only survived possession by a warp entity, but also managing to do what seems impossible, casting out the daemon from their own bodies. The experience of sharing a mind with a daemon has completely changed their outlook on the universe, and given them a unique understanding of Chaos and warp entities. The Illuminati form a secret society, said to be unknown even to the Emperor.
In the process of freeing themselves from daemonic possession, they have also mastered the Chaos within themselves - accordingly the Illuminati are among the very few allowed to enter the fabled Black Library, the Eldar race's repository of knowledge of Chaos. Through this they gained even greater understanding - they have learned of the Fall of the Eldar and origins of the Emperor.
The Illuminati were first introduced in the late 80's "Realm of Chaos: Slaves to Darkness" book. It is uncertain where they stand in the present chronology of the game, or even if they are a part of it at all. As the Illuminati plot thread was linked to the Starchild/Sensei storyline, publisher Games Workshop may have abandoned the Illuminati storyline as the Starchild/Sensei plot was written off as yet another manipulation of Chaos God Tzeentch (in the 3rd edition rulebook), although other, more recent literature seems to imply that it is still viable, such as seen in Xenology.
