Librarian

Space Marine Librarians are psykers who survive a Chapter's rigorous screening and training to bend The Warp for the benefit of their Battle Brothers. Librarians also record the great deeds of their Chapter.

Librarians are often isolated from the rest of the Chapter, as they carry with them the abilities the Space Marines are expected to abhor and purge in all other beings.

Overview
The Librarians are assigned to Companies, however their actual place in the Chapter is with the Librarium. As the name suggests, the Librarium is a place within a Space Marine Chapter's Fortress Monastery where the vast knowledge base, gathered over millennia of hard fought battles and great crusades, is stored.

The Librarium is maintained and governed by the Chief Librarian, Epistolary, and maintained by Codicers and the Lexicanum. Within the Space Wolves' Librarium is an armoured room for controlling the base's defense systems.

Librarians of rank Codicer and above deploy their psychic powers in combat. These include the ability to project their consciousness above the battlefield in a ritual that commences with the recitation of the Litany of Sight Beyond Sight. Doing so opens a wound on their forehead exposing their psychic Third Eye, which allows them to view locations that would normally be obscured.

Librarians can channel psychic energy (often through Force weapons) to deal greater damage than a normal mêlée attack would allow. They can also read the minds of others, unless protected by psychic shields.

Off the field of battle, the Librarians are responsible for maintaining and adding to the records of the Chapter, attending to the Chapter's annals and the collective knowledge built up over millennia of service.

Origin
The records about the beginning of the Space Marine Librarian contingent don't agree between scholars, however according to Saphrus the Ancient, in the time of Pre-Heresy the Emperor of Mankind himself held a council on the planet Nikaea, bidding that both sides present their position about the use of psychic and sorcery powers. Both sides argued each other to a standstill, and it was only the intervention of a contingent of Space Marine Librarians from other Legions that presented a compromise. (One being the Primarch Magnus, who had in his Legion a high number of Marines who had undergone psychic mutation.)

The proposal was made that while the education of psykers to best serve humanity should be made a priority, the conduct of arcane sorcery would be outlawed as an unforgivable heresy. This compromise was made law without a provision for rebuttal, and the Edicts of Nikaea have stood for ten thousand years as official Imperial policy.

Some Primarchs accepted the ideas of Magnus into their own Legions, while others refused to deal with what they saw as sorcery by another name.

Each Chapter is continually vigilant to ensure that recruits will not taint the gene-seed of the Chapter through mutation. However, the psyker mutation is often encouraged, and these Marines are inducted into the corps of Librarians.

Recruitment
Aspirants and neophytes of all Space Marine chapters are screened by the Chapter Librarians for signs of psychic potential. Those who possess the potential to become a Librarian are then forced to undergo the same trials and sufferings all Space Marine neophytes face, but then also have to learn to harness their powers and protect their minds from the dangers of the Warp. As Space Marines are far stronger mentally and physically than any ordinary man, their flesh is ideal for daemons to inhabit. For a Librarian, each day is a walk along a narrow path which, should they stumble or stray from, leads ultimately to madness and possession.

Training
The course to becoming a Librarian is a very difficult one, as they must not only be strong enough to survive their training, but possess enough mental discipline to fend off the daemons and entities of the Warp, as these creatures see the enhanced form and mind of a Librarian as a strong prize.

Ranks

 * Lexicani are Space Marine Librarians who are not generally seen in combat. Most of the time, they are found within a Chapter's Librarium, storing the vast amounts of information the Chapter has gathered over years of conflict and crusade. With more training, they can become Codicers and be given significant combat assignments, able to harness their powers with greater clarity. Lexicanum Librarians are often distinguished by their lack of a Psychic hood and helmet, usually appearing very similar to their Brother-Marines except for the blue Power Armour that Librarians wear.


 * Codicers are Space Marine Librarians who have enough control over their powers to go into combat. They usually receive further training to become Epistolary Librarians, so they can use multiple psychic powers in combat. They usually do not have a Psychic hood, but rather devices more useful than that of their Imperial Sanctioned Psyker brethren.


 * Epistolaries are powerful Space Marine Librarians and their primary role, while not on the battlefield, is that of chief psychic communications officer. Even on the battlefield he can send and receive psychic messages. In the 4th edition of Codex: Space Marines they count as the more powerful Librarian choice. They have more mastery over their psychic powers allowing them to use more than one in combat. They wear a Psychic Hood and carry a Force Weapon and have access to the Space Marine Armoury.


 * The Chief Librarian is the strongest and most psychically attuned Librarian of a Space Marine Chapter, who all other Librarians in the chapter bow to. He is master of the Librarium and is a living encyclopedia of knowledge due to his unrestricted access to the texts of old. He is also a greatly talented Psyker, stronger then even the Epistolary Librarians. Chief Librarians often lead forces or assist the Chapter Master in battle. Chief Librarians also spend a great deal of time training their lesser Codicer and Lexicanum brothers.

The codex role of Librarian in the Space Wolves Chapter is taken by the Rune Priest. It is his duty to keep the knowledge of the chapter’s history, reciting the great sagas of old. The entire history of the Chapter is passed through these sagas; therefore the duty of keeping the knowledge is a heavy one indeed. The Rune Priests duty as a Librarian is carried out through the shamanic rituals of the Fenrisian traditions. One common power is to be able to summon a storm across the battlefield, covering the army's advance.

Combat Doctrine
These psychically-charged warriors are trained to use their abilities in the field of battle, as both weapons and tools of precognition.

The Librarians use a Psychic Hood to suppress their enemies' use of psychic powers; the hood's wires tap directly into the brain and act as an extension of the wearer's consciousness, allowing him to detect nearby manipulations of the warp and to channel them through a series of crystals designed to augment the Librarian's willpower. When deployed, a Librarian's psychic might exceeds even that of the Eldar Farseers in sheer brutality. Librarians wield potent force weapons, psychically-charged power weapons that allow the Librarian to detonate a mental blast with each strike. In-game, this is represented by the ability to instantly kill any wounded model, regardless of their total wounds remaining.

Appearance
A Librarian's power armour is blue with the chapter icon on the left shoulder pad and a horned skull (the symbol of the Librarium) on the right. Most wear a white robe over their torso which typically bears a stitched symbol of their rank (usually that of a Codicier or Epistolary). Most carry scrolls and copies of ancient texts with them, either as badges of office or as references of wisdom. Almost all Librarians above the rank of Codicier wear psychic hoods, powerful helms which contain crystals that amplify the wearer's abilities and strengthen their control over them.

Some Librarians go to battle in Tactical Dreadnought Suits - better known as Terminator Armour - which is painted and decorated in the same manner as their fellows clad in normal power armour, and also includes a psychic hood. Because of the size of Terminator armour, those worn by Librarians are modified to carry crystals (similar to those fixed within psychic hoods) inside the finger tips and palm, so that a Librarian can still use his powers while encased within the protective suit. However, a Librarian in Terminator armour may wish to simply use his force staff to manage and exert his power, and wield a ranged weapon in his free hand.

Notable Members
Each Chapter has a Chief Librarian, the strongest and wisest psyker in the entire Chapter. One often becomes the Chief Librarian by virtue of experience or by demonstrating exceptional self-control and willpower, vital traits for an Imperial psyker. These are some named Chief Librarians:
 * Chief Librarian Tigurius: Tigurius is the Chief Librarian of the Ultramarines, a masterful telepath rumoured to be the most powerful of all Adeptus Astartes psykers, as it is said that he touched minds with the Tyranid Hive Mind and survived - a feat previously considered impossible, as the psychic weight of the Hive Mind would overload the telepath and subsume his soul. His equipment enhances the power of his psychic abilities, doubling their maximum range.
 * Chief Librarian Mephiston: Mephiston of the Blood Angels not only survived the Black Rage, but also greatly benefited from it. His gaze is so terrible even the most disciplined heroes would quiver in his wake, and he possesses the ability to fly under his own power. He is the most close-combat oriented Librarian, and perhaps the greatest Space Marine swordsman in the universe.
 * Ezekiel, Grand Master of the Dark Angel Librarians: Ezekiel is the greatest of all Dark Angel Librarians and has the ability to transverse the minds of his enemies, predicting their moves before they think of it. His Mind Worm psychic power can cause an opponent's brain to literally melt out his ears.
 * Njal Stormcaller: While not officially a Librarian, Njal Stormcaller serves the Space Wolves chapter as their senior Rune Priest, their radically altered equivalent. There are now rules for him in the newest edition of the space wolves codex.
 * Ahriman of the Thousand Sons: Although not a Librarian of the Loyalist Chapters, the Chaos sorcerer Ahriman was infamous for his journeys throughout the galaxy, ransacking vaults and looting any artefacts he could get his hands on. This caused many custodians paranoia and has resulted in the destruction of many artefacts. Ahriman is also responsible for turning the entire Thousand Sons Legion into mindless automata with his infamous Rubric of Ahriman.
 * Sarpedon, Chapter Master of the Soul Drinkers: Sarpedon was the Chief Librarian of the Soul Drinkers, currently excommunicate. He possesses the unique psychic power known as "The Hell" along with a physical mutation giving him extra appendages, manifesting in the form of chitinous spider legs which were unwillingly bestowed upon him by the Tzeentch Daemon Prince Abraxes.