Librarian - Librarian: A Librarian is a Firstborn or Primaris Marine combat psyker of the Space Marines who survives an Adeptus Astartes Chapter's rigorous screening and training to bend the powers of the Warp to their will for the benefit of their fellow battle-brothers and in service to the Emperor of Mankind. Beyond their psychic duties, the Librarians of the Astartes are also expected to record the great deeds of their Chapter and maintain the Chapter's storehouse of ancient lore, the functions for which they are named.A Librarian is often estranged from the other members of his Chapter. This is usually because the psychic abilities he possesses are what his brother Space Marines are often expected to abhor and purge in most other beings.Space Marine Librarians use their abilities to serve the various undertakings of their Chapter; however, their actual place in the order of battle is always with the Librarius in a Codex Astartes-compliant Chapter. As the name suggests, the Librarius is a place within a Space Marine Chapter's fortress-monastery where the Chapter's vast knowledge base, gathered over millennia of hard-fought battles and participation in engagements the length and breadth of the galaxy, is stored. Space Marine Librarians are generally classified in one of four ranks, each with its own duties and responsibilities within the Librarius. The Librarius is led by the Veteran Space Marine psyker who bears the rank of Chief Librarian. The Chief Librarian is usually, but not always, the most venerable of his psyker brothers.The Chapter's most potent battlefield psykers are the epistolaries, each a hardened veteran of many wars. The Chapter's psychic communications and the Librarius' records are maintained by the codiciers and the lexicani (sing. lexicanium), respectively. These ranks and responsibilities may vary from Chapter to Chapter.The Imperium is eternally vigilant for the taint of mutation. Space Marine Chapters are, if anything, even more careful to ensure that their gene-seed is not polluted. Apothecaries rigorously screen potential recruits for any sign of genetic deviation, but not all mutation is physical. Psychic talent is a mutation too, and is at once the most dangerous and the most useful. The training of a Chapter's nascent psykers is one of the many responsibilities of the Librarius.Few normal Space Marine recruits survive the rigorous training, enhancement and indoctrination required to join a Chapter. Amongst Librarians, the attrition is far worse. The aspirant must not only endure everything a normal recruit would, but also have a strong enough spirit to withstand the moulding of his mind. A recruit must be taught how to hone and wield his powers, and how to protect himself from the Empyrean's innate hazards. A Librarian faces a thousand enemies before he even goes to war –- to the creatures of the Warp, his mind is a choice prize. Each day is a walk along a precipice, and a false step can see him tumble into madness.If a recruit survives the rigorous testing, he joins the Librarius as a lexicanium, rising through the ranks to become codicier, epistolary or perhaps even the Chapter's Chief Librarian. He will use his abilities to pierce the Warp and provide the means for astrotelepathic interstellar communication, as well as to identify others of his own kind. He will judge them as he was himself once judged, scrutinising potential candidates and peers for frailty of mind or spirit. A moment's weakness can unleash untold evils, and vigil must be kept against any wavering of purpose.In addition to training psychic recruits, the Chapter's Librarius is also charged with recording the history of the Chapter. Librarians hold a functionary rank, describing their role within the Librarius as well as their position within the Chapter's hierarchy. Lexicaniums, for example, are responsible for preparing reports of battle for the Chapter's records, whilst codiciers provide a strategic overview of the whole theatre of a war. After many solar decades of study and book-keeping, a Librarian will be well-versed in the history and lore of his Chapter, and both his wisdom and counsel will be highly regarded by the Masters of the Chapter.Most Librarian battle-disciplines focus on enhancing their already formidable combat prowess. Many can use their psychic powers to throw powerful energy bolts, project telekinetic force shields or increase their might to demigod-like proportions. Some can step outside of the flow of time, slow the enemy's movements or redirect bullets with the sheer power of their minds.Even so, the most skilled Librarians can master more subtle gifts, learning how to read the Emperor's Tarot and sense the movement of Daemons through Warpspace. A Librarian can feel the psychic shock waves that herald the arrival of a voidcraft from the Warp, or the turmoil they leave in their wake as they depart realspace.These powers, and more, set Librarians apart from their battle-brothers, yet their presence is always welcomed on the field of battle. In all of the Imperium, there are few greater warrior mystics than Space Marine Librarians, with their potent combination of the prowess of an Adeptus Astartes with the unearthly powers of the Warp.