Psyker

A psyker, in the Warhammer 40,000 universe, is an individual with psychic powers, capable of accessing the Warp. This is both a blessing and a curse; though psykers are often able to achieve spectacular feats with their abilities, the Warp is a perilous place, and whenever a psyker uses their abilities there is a chance that they will be subject to the Perils of the Warp. Death is one of the milder results of this; extremely unlucky psykers might actually become possessed by Daemons and used as a gateway from the Warp into the physical world.

The different races of the setting perceive psykers in different ways. The Imperium of Man regards most psykers as extremely dangerous because of the threat of Chaos possession, and thus the Inquisition hunts them down so they can either be sacrificed to the Empra or sanctioned and made to serve the Imperium (under an inquisitor's watchful eye). The Eldar are a strongly psychically-attuned race, and their most powerful psykers become Farseers and leaders of their people. The Tau have almost no presence in the Warp and thus their race has no psykers whatsoever, although some of their vassal races have psychic abilities. The Necron are anathema to psykers, since they are extremely vulnerable to the powers of the Warp, and they plan to close the Eye of Terror and shut off the Warp from the physical world entirely, so that they might begin their conquest of the galaxy unopposed once more. Orks have their own psykik energy in the power of the WAAAAAAGH, which they tap via Wyrdboys.

Culexus assassins are psykers' worst nightmare, though they are very friendly.

• 
• 

  the reason you should never invite psykers to your games night