All Grey Knights possess a degree of psychic ability which is further developed and enhanced by their years of training on Titan. While only a handful of Battle-Brothers ever achieve the levels of power commanded by the Chapter’s Librarians, they are all capable of manifesting certain powers and abilities, especially in the company of other Grey Knights where they can combine their gifts to create great effects and more devastating psychic attacks. Grey Knights do not suffer the corruption of the Warp and are nigh invulnerable to its longer-term effects. While daemonic forces may effect them physically, or even confuse them, they are the purest of Space Marines and the most resistant to the powers of the Empyrean. Grey Knights are far less susceptible to insanity than normal men and their