The Ordo Malleus was founded shortly after the Horus Heresy, and was one of the two original Ordos of the Inquisition. The Ordo Malleus concerns itself with the daemonic threat that faces the Imperium, and for thousands of years have waged a covert war for humanity's survival. Every single Inquisitor has sworn to pledge their every hour to seeking out and destroying daemonic threats wherever they may appear.
An Inquisitor of the Ordo Malleus has at his disposal all the Imperium may offer. He will not hesitate to recruit local troops at a moment's notice, or to call upon a detachment from the Space Marines. No force is considered too strong to combat such a threat, and to prevent the further spread of Chaos, all records of their actions are eliminated. Those with skills too useful to waste are mind-scrubbed and brainwashed to forget, while any other forces are consigned to labour camps or executed.
When the level of Daemonic infestation is so much that even an Inquisitor can not handle it, an Ordo Malleus Inquisitor can call on the Grey Knights, the Chamber Militant of the Ordo Malleus. Surpassing even their fellow Marines in power, the Grey Knights have the skill and determination to destroy any daemon and send its presence back into the Immaterium.
Without the Ordo Malleus and the Grey Knights, the Imperium would not survive.
In combat, the Inquisition deploys a variety of troops, as an Inquisitor has the authority to command almost any citizen of the Imperium. The forces of the Ordo Malleus could include anything from the Imperial Guard to the Space Marines.
The Grey Knights are a specialized branch of the Ordo Malleus that essentially serve as shock troops for the ordo. They are rumored to be derived from the Emperor's gene seed. Although they are essentially a branch of the Space Marines, (the 666th chapter) their organization is slightly different. Companies of Grey Knights travel throughout the universe to quell any major outbreaks of chaos. Squads of Grey Knights are lead by Justicars, who are in turn lead by brother captains. They are also not centrally commanded, as are most Space Marine chapters. Each company is self sufficient.
Grey Knights are made up of the strongest humans the imperium can offer, and their training is much more rigorous. They are trained to fear nothing, and are psychically trained to resist chaotic influences on them. Candidates are brought to Titan (Saturn's largest moon) the Grey Knights' home base. On Titan is a fortress where all the fallen Grey Knights are interred and where all the candidates are trained.
The Knights are issued with the best equipment possible. Their armor shields them against psychic attacks, and is physically repelling to daemons. They carry stormbolters on one wrist, and carry a nemesis force-weapon, which is typically a halberd that is charged by the Grey Knight's mind. Heavy weapons squads (Purgation Squads) carry special double barreled flamethrowers that are loaded with holy oils, called incinerators, and psycannons, which carry psychically charged bolts that can tear through force fields and armor.
Perhaps the most distingushing part of any Grey Knight is his weapon. All Nemesis Force Weapons are crafted with the purest materials to the highest standards. Each weapon is also unique as it is tailored specifically to the wielder's psychic energies. Because of this, no one can use a Nemesis Force Weapon other than the owner. The weapon will accumulate power as its owner gains experience. Higher ranking knights can destroy even Terminator armour with their Force Weapon. Grand Masters can kill monstrous creatures outright with a single stab. Nemesis Force Weapons normally take the shape of a sword or halberd but can also be an axe or any other sharp weapon.
Brother-captain Stern served the Grey Knights for many long years. His most famous act was when he banished the Lord of Change M'kachen back into the Warp for one hundred years and a day. When the vengeful daemon finally returned he vowed to send Captain Stern into the realm of the dead no matter what the cost. He appears on the battlefield to face Stern every chance he gets.
~First Book of Indoctrinations
~Inquisitorial motto
~Inquisitorial motto