Sisters of Silence - Daughters of the Anathema: The most singular thing about the order was that each and every woman within its ranks was an "Untouchable," a rare genetic sub-set of Humanity who cast no soul-shadow in the Warp, and whose minds are completely immune to psychic assault and an anathema to all those with psychic powers.Their mere proximity is enough to cause psykers discomfort and pain, and in truth they will even sow fear and disgust in the hearts of those whose minds are without the psyker's gift, no matter how strong-willed they may be. It is a simple and irresistible reaction to the fundamental "wrongness" of the Untouchable or as it is often put more melodramatically, "a body without a soul." This curious and macabre phenomena goes beyond simple absence, as one might feel disturbed by a mannequin or automata which apes Humanity but remains unalive -- instead it is an observably preternatural effect which seems to strike deep against the fundamental unconscious perceptions of all living beings as something malignant and contrary to the natural order of existence.There appears to be perceptible degrees of this effect which vary from individual to individual, with some Untouchables "stronger" in the phenomena than others, and it is from the strongest of these that the Sisters of Silence are drawn. It is also noteworthy to the extent that the disturbance caused by an Untouchable is evident not only to Humanity, but also all other lifeforms and xenos species encountered to some greater or lesser extent.In proof of this there are many recorded incidences of the unsettling effects of Human psychic Nulls being enough even to unnerve the blind brutal savagery of rampaging Orks, while to the Aeldari xenoform, psychically attuned as every individual of their species is, the presence of a Human Untouchable is a thing of acute, existential horror. The most potent and perhaps shocking power of the psychic Null however is that which makes them the perfect hunters and slayers of psykers; Untouchables such as the Sisters of Silence are almost impossible to affect with Empyreal powers. Their minds cannot be taken over, their perceptions cannot be altered and their bodies cannot be possessed by Warp entities.Even the cruder but more direct manipulations of the environment or ambient energy by the psyker such as conjured fire or the hurling of debris by telekinetic force is lessened and sometimes negated outright by the Untouchable's sheer proximity. With psychic Nulls such as the Sisters of Silence, specifically chosen for the "strength" of their gift, it is the case that their minds are not simply absent or inert to a psyker's mental perception, but howling abysses of darkness that not only negate psychic force directed at them, but actively interfere with the flow of Warp energies into realspace around them.The profoundly phobic reaction they engender extends to both Human and xenos psykers as well as entities and creatures of the Empyrean like Daemons, their mere presence a debilitating toxin. Further, there are those among the Sisterhood who through arcane training and practice -- and whose nature has never been revealed to outsiders -- are able to develop their "Null" abilities further until they are actively disruptive enough to make any use of psychic power in their presence extremely hazardous.These Sisters are honed into the "Oblivion Knights," and within their order they are the foundation stone of an elite force specially tasked not with the day-to-day enforcement of the Great Tithe, but the destruction of alpha-level rogue psykers and the ceaseless training for battles of this deadly kind.In their studies, the Sisters of Silence read many of the great texts that were found in the towering stacks of the Libraria in the Somnus Citadel on Luna, from the earliest surviving volumes of the Psykana Occultis to the Voiceless Judgements of Melaena Verdthand. Within these tomes of psychic research and ancient lore, the young Sisters-in-Waiting learned much concerning the nature of the witch.They came to believe that skill in the Power Sword and bolter were but one half of a sister's armoury, for knowledge of their quarry carried equal weight. In this quest they had learned a great deal about the extremes of psykerkind to be found in the Human-settled galaxy. The sisters learned to ferret them out, combat them and, if need be, execute them with extreme prejudice for the greater good of all Mankind.