Psyker - Imperium of Man: The genetic mutation which grants a Human being the ability to draw upon the psychic energy of the Immaterium has become increasingly common since the Neolithic Age. However, what is known is that Human psykers were only first mentioned in the historical record towards the end of the 22nd Millennium, making a sudden appearance on almost every Human-settled world within a relatively short span of time, not long before the onset of the Age of Strife.This change was the harbinger of Mankind's slow evolution into a fully psychic species much like the Aeldari, who will be more intelligent, more capable and ultimately more peaceful than Humanity is at present. Unfortunately, this process has been quite uneven and even the most powerful Human psykers still have minds that have not developed to the point that they can touch the Warp with the level of control wielded by the Aeldari Seers.As such, because of this lack of mental development and Mankind's own still deeply flawed, covetous nature, most Human psykers always run a substantial risk of being possessed by the Daemonic entities of the Warp and spreading the death and destruction of Chaos wherever they go. It is for this reason that the Emperor of Mankind largely banned the use of psychic powers throughout the Imperium of Man save in a few notable exceptions in 001.M31 at the Council of Nikaea during the Great Crusade.Psykers, although justifiably feared throughout Humanity's history because of their extraordinary powers and the equally extraordinary dangers they sometimes unleashed on those around them, serve several vital roles within the Imperium today under several of the exceptions laid out by the Council of Nikaea some ten millennia ago.Psykers are too dangerous to remain at liberty on the Imperium's myriad worlds; their minds are susceptible to Daemonic possession as their strong presences in the Warp can serve as gateways into the material universe for all kinds of Warp entities if they are weak or undisciplined with their powers. Uncontrolled, they can intentionally or unintentionally cause the destruction of entire worlds and have done so in the pre-Imperial past, such as during the terrible days of the Age of Strife.Humans found to be bearing the psychic mutation, if they are not simply killed, are sent to Terra aboard the infamous Black Ships of the Inquisition which endlessly traverse the Imperium. All Human psykers have an ordained role to play as loyal servants of the Imperium if they have the willpower to control their abilities and not become a danger to others. Their exact role depends on the psychic powers they manifest and their strength of character and will, though psykers who have some use for the Imperium are known as "Sanctioned Psykers" while individuals who manifest unusually strong psychic powers often become "Primaris Psykers," the most powerful Human psykers in existence.Sanctioned Psykers serve within the Astra Militarum and as Librarians in the Space Marine Chapters, employing their powers in battle as well as for civil duties. Imperial Navigators use their psychic "third eye" to determine safe paths through the Immaterium for Imperial voidcraft using the faster-than-light Warp-Drive employed by all Imperial starships. Astropaths provide faster-than-light communication as their telepathy is not confined to the speed of light since their messages travel through the Warp much as starships use the Warp to make interstellar jumps.Thousands of psykers who lack the mental discipline and willpower to safely serve the Imperium are sacrificed every standard year to sustain the Emperor's psychic presence in the Warp, and thousands more must constantly be drained by Him to power the Astronomican, which broadcasts a potent telepathic signal through the Warp which is used as a point of reference by starship Navigators. However, the Imperium of Man also ruthlessly executes countless less-fortunate psykers who are seen as mutants, Heretics, potential threats to their homeworlds, or gateways to the Daemons and corruption of Chaos.Psykers first emerged amongst Mankind in the middle part of the long distant Age of Technology, a period of Human history about which all but nothing is remembered in the 41st Millennium. Since that time, ever-greater numbers of Humans have been born with the ability to wield psychic powers, and others still come into such powers later on in life. This phenomenon has been the subject of study, debate, superstition, prejudice, intolerance, and even open warfare throughout the ages, and all manner of meanings have been read into it.Some claim that Humanity is undergoing the birth pangs of a new phase in its evolution, and can look forward to an age when the species transcends to an entirely different level of existence. Most interpretations are far less optimistic, however, and those with knowledge of such things point to the fate of the ancient Aeldari Empire as a warning of what doom awaits Mankind. Others still hold that this gradual and ever-increasing evolution is the doing of the Emperor Himself, who exists to shepherd the entire species into its new age. Those of a notably Puritan persuasion hold that for every psyker born, a thousand twisted mutants are spawned first, as if the process itself was abhorrent to the Emperor, to nature or to both.Whatever the truth of the matter, it is evident that more and more Human psykers are being born or coming into their powers with every passing generation. The bleak holds of the Black Ships grow ever more bloated with those swept up in the psyker culls.With this increase, the risk of Daemonic incursion and Enslaver plague in realspace grows worse, for should one powerful but uncontrolled psyker go undetected, the slavering denizens of the Warp might breach reality itself and come pouring in, bringing the doom of Humanity with them.