Inquisition

"...the Inquisition merely performs the duty of its office. To further fear them is redundant, to hate them, heretical. Those more sensible will place responsibility with those who forced their hands..."

- Captain Gabriel Angelos of the Blood Ravens Space Marine Chapter after the Inquisition's Exterminatus of Typhon Primaris

The Inquisition (The Holy Orders of the Emperor's Inquisition) is a secret organisation that exists outside the standard administrative hierarchy of the Imperium of Man. The Inquisition acts as the secret police force of the Imperium, hunting down any and all of the myriad threats to the stability of the God-Emperor's realm, from the corruption caused by the Forces of Chaos, heretics, mutants and rebels, to assaults from vicious alien species like the Tyranids, Orks or Dark Eldar. The Inquisition's infamous sigil was derived from the personal heraldry of Malcador the Sigillite, the Regent of Terra during the Great Crusade and the Horus Heresy and the second most powerful psyker in the Imperium of Man after the Emperor of Mankind himself. It was Malcador who first created the secret organisation that would later become the varied Ordos of the Inquisition at the start of the Heresy on the orders of the Emperor. The Master of Mankind had ordered the Sigillite to find a group of men and women of an "inquisitive nature" to search out the enemies of the Imperium, whether they lay within or without.

History
To those who know of such things, the Inquisition is widely believed to have been formed by Malcador the Sigillite on the orders of the Emperor of Mankind at the start of the Horus Heresy. The new organisation had been created from 4 lords and administrators of the Imperium and 8 Space Marines drawn from the Loyalist Astartes and the Traitor Legions who had remained loyal to the Emperor when the rest of their Legions had turned to Chaos. In this way they had displayed an unusual purity of mind and resistance to corruption. These 8 Astartes were gathered from across the galaxy during the Heresy by Nathaniel Garro, the former Battle Captain of the 7th Great Company of the Death Guard Traitor Legion who had stayed loyal to the Emperor and left Istvaan III behind on the Frigate Eisenstein to warn the Emperor of the Warmaster Horus' treachery. The foundation of the Inquisition is shrouded in mystery and is still a much-debated subject amongst Imperial scholars.

It is generally accepted that the Inquisition only solidified into its truly modern form some time in the 32nd Millennium after the formal birth of the Imperial Cult as the state religion of the Imperium, some 800 years after the end of the Horus Heresy, although its essential components and apparatus (the Black Ships, the "Witch Hunters" of the Sisters of Silence, etc.) were active in the Imperium during the Great Crusade before the Heresy began. newly uncovered sources indicate that the Inquisition had 12 key founders, who were active before, during and after the Great Crusade. As noted above, at the start of the Heresy the Emperor had ordered his regent, Malcador the Sigillite, to gather men and women of unswerving loyalty and devotion who might seek out the hidden foes of all Mankind. Malcador presented 12 such individuals to the Emperor, 4 of them Imperial administrators of "an inquisitive nature" and 8 of them Space Marines, including Captain Garro and a few other Loyalists he had been tasked with gathering from across the galaxy who were drawn from the remaining Loyalist Astartes Legions or who had escaped their Traitor Legions after the massacre at Istvaan III. These 8 Astartes would go on to become the first of what would later be known as the Grey Knights, the Chamber Militant of the Inquisition's Ordo Malleus, the Demonhunters. There were originally only two Ordos (the Ordo Malleus and the Ordo Xenos) within the Inquisition, but a third (the Ordo Hereticus) was added after the terrible events of the Age of Apostasy in the 36th Millennium to prevent a future Reign of Blood and "Plague of Unbelief".

Ordos of the Inquisition
In early editions of Warhammer 40,000, the Inquisition was a single, undivided organization -- purposefully outside the bureaucracy of the rest of the Imperium -- with a single inner order, the Ordo Malleus. The Malleus' purpose was to police the Inquisition itself. Its other, secret purpose was dealing with the threat of Chaos.

Today, the Inquisition is divided into a series of organisations known as Ordos. Each Ordo is responsible for assessing and combating a threat to humanity. There are three major Ordos devoted to combating threats Within, Without, and Beyond.

As of the end of the 41st Millennium, the three Ordos Majoris or major Ordos are: It should also be noted that there are some freelance Inquisitors-at-large who are not part of one specific branch of the Inquisition. There are also several minor Ordos that have more specific purposes than those outlined above.
 * Ordo Malleus - Known as the Daemonhunters, or the Order of the Hammer, the Ordo Malleus are sworn to defend the very soul of Mankind, concentrating on the defeat of those enemies of Humanity that dwell in the warp; the so-called "enemy beyond." They primarily concern themselves with destroying Daemons and other servants of Chaos. The Chamber Militant of the Ordo Malleus is the elite Grey Knights Space Marines Chapter.
 * Ordo Xenos - Also known as the Alien Hunters, or the Order of the Aliens, the Ordo Xenos are dedicated to the defeat of the Xenos threat; the enemy without. They actively seek out and eliminate alien influence and corruption within the Imperium. The Ordo Xenos' Chamber Militant are the Veteran Space Marines of the Deathwatch, who usually operate in small units known as Kill-teams. The Deathwatch are not a true Adeptus Astartes Chapter; instead their ranks are filled from Space Marines seconded from other Chapters who remain as part of the Kill-team for several years before returning to their home Chapter.
 * Ordo Hereticus - This Ordo is also known as the Witch Hunters, or the Order of the Heretics. The Ordo Hereticus is the scourge of the traitor, the witch, Mutants, rogue Psykers and heretics. The interests of its members are aligned towards the combating of threats broadly classified as arising from within the great bulk of Humanity; the so-called "enemy within." The Ordo Hereticus' Chamber Militant are the Sisters of Battle, the Orders Militant of the Adepta Sororitas.

Ordos Minoris
Subordinate to the Ordos Majoris are several smaller Inquisitorial organizations, known as the Ordos Minoris. These minor Ordos are significantly smaller than the main three, and are often formed to combat specific, rather than broad, threats to the Imperium. Most of these Ordos Minoris are largely unknown, even to other members of the Inquisition. Many are little more than cabals of Inquisitors allied against a common threat, while others are in essence specialised sub-Ordos. Other, nigh unknown Ordos might interest themselves in matters so esoteric or specialised they are entirely unknown to their fellows:
 * Ordo Chronos - This mysterious and incredibly obscure Ordo was formed to investigate the potential ramifications of time travel through the Warp, particularly the potential for deliberate manipulation of this phenomenon. This now-defunct Ordo disappeared under mysterious circumstances, and their eventual return remains the subject of legend amongst the few who know they ever existed.
 * Ordo Hydra - This Ordo was an extremist offshoot of the secret society known as the Illuminati that was dedicated to the use of certain extreme measures to destroy the existence of Chaos in the universe once and for all. It was composed mainly, but not entirely, of Illuminati who are also Inquisitors, some of whom occupied extremely high ranks within the Inquisition. The Ordo Hydra is often cited as an Ordo Minoris, however the Ordo Hydra was a group who used a particular tool rather than a group who combated a specific threat, and so despite their name they were perhaps better described as an Inquisitorial Cabal. They were defeated by the actions of the Inquisitor Jaq Draco who prevented them from unleashing a plot to unite all of humanity as a single hive mind. This was intended to provide Mankind with the ability to destroy the Chaos Gods once and for all, but was more likely to result in the birth of a fifth major Chaos God who would render the human race extinct and guarantee the final victory of Chaos.
 * Ordo Militum - This Ordo has the duty of monitoring the Imperium's military bodies, such as the Imperial Guard, the Imperial Navy, the Commissariat, the Sanctioned Psykers of the Adeptus Astra Telepathica, the Adeptus Astartes (although see below), and -- together with the Ordo Hereticus -- the Adepta Sororitas.
 * Ordo Obsuletus - The Ordo Obsuletus' task is to monitor and validate unexplained phenomena and miracles said to have occurred across the Imperium. Since the Dark Gods, especially Tzeentch, are not above sacrificing whole hosts of their mortal servants to ensure that a plot comes to fruition, it is the duty of the Ordo Obsuletus to investigate whether a miracle is a genuine manifestation of the Emperor's will, or yet another convoluted xenos or Chaotic deception. Events such as the appearance of the Legion of the Damned and the reappearances of Lord Varlak after his incineration on Korsk II, then again on Necromunda, and a third time on Vanor XXI, are their area of expertise. The Ordo Obsoletus is often cited as being an Ordo Minoris, but this is merely conjecture. It is possible that the Ordo Obsoletus is not, strictly speaking, an Ordo at all, but a regional Inquisitorial Conclave that refers to itself as an Ordo.
 * Ordo Sepulturum - This Ordo is one of the smallest and newest of the Ordos Minoris, formed during the 13th Black Crusade. Their focus is the relatively new threat presented to the Imperium by the emergence of the Plague Zombies and the Nurgle-spawned Zombie Plague.
 * Ordo Sicarius - This Ordo is tasked with investigating, moderating and controlling the Officio Assassinorum in the wake of the deadly events that occurred during the Reign of Blood in the Age of Apostasy of the 36th Millennium.
 * A seventh minor Ordo, whose name is unknown, develops methods to limit the independence of the Adeptus Astartes. It was founded during the Horus Heresy and has since been almost forgotten. They were mentioned in the Space Wolves novel Wolfblade, where the Assassin Xenothan used a poison made from the first blossoms of the Mecurian Swamp Orchid that could temporarily paralyse Space Marines. It worked by disrupting and confusing the Space Marines' genetically-engineered poison-neutralizing gland, effectively turning it into a weapon against the Astartes. Note, that as the aforementioned Ordo Militum is a relatively early and little-seen aspect of the Inquisition, this could actually be a reference to it rather than a separate Ordo Minoris.

Role of the Inquisition
The Inquisition is immensely powerful, and the only individual that is exempt from its scrutiny is the Emperor himself. If he has good cause, an Inquisitor may demand any service from any Imperial citizen, up to and including the High Lords of Terra. The Adeptus Custodes who guard the Emperor's palace and person are exempt from conscription, because their duty to the Emperor is clear and unchanging. When it comes to the Adeptus Astartes, Inquisitors often show some discretion, as Space Marine Chapters are often willing to come to blood over any infringement on their Emperor-granted autonomy. However, not even the Adeptus Astartes are immune from the Inquisition's scrutiny and justice, and entire worlds have been destroyed in order to cleanse them if they were deemed traitorous.

Inquisitors also have absolute power to judge and execute supposed heretics, mutants, unsanctioned or rogue psykers and the like, with no appeal save the intervention of another Inquisitor. Practically, all possible verdicts are death sentences, although the means by which they are achieved differ. Traitors, the worst grade of offenders, are considered irredeemable and will be quickly executed. Heretics may be redeemed, often after considerable amounts of torture, and may receive absolution through death in service to the Imperium. This service may consist of arco-flagellation, conscription into Imperial armies, becoming the operator of one of the Adeptus Ministorum's Penitent Engines or, in the case of penitent psykers, being sent to Holy Terra to become new psychic fuel for the Golden Throne. Certain traitors deemed useful to the Inquisition may in extremely rare cases be mind-scrubbed, their old memories and identity erased and replaced with one loyal to the Inquisition. If it is beyond their means to track down and kill a particular individual or organization, an Inquisitor can simply declare the offending entity Excommunicate Traitoris, stripping them of whatever rights they may have had and as such marking them as a target fit for extermination by any and all loyal servants of the Emperor.

If the Inquisitor deems it necessary he or she can attach an official stigma to a dangerous heretic, Traitor or alien race. Each of the major Ordos has a different official stigma which pertains to their primary enemies. These stigmata include the Extremis Diabolis for the Ordo Malleus, the Xenos Horrificus for the Ordo Xenos and the Hereticus Abomini for the Ordo Hereticus. The Inquisition will also use its delegated power from the High Lords of Terra to declare "tainted" Space Marine Chapters or other Renegade Imperial military units or individuals Excommunicate Traitoris. The Chapter or other unit will then usually be hunted down by the Grey Knights or the Sisters of Battle, usually resulting in the Chapter fleeing to the Eye of Terror or the Maelstrom (if it has not already done so). The Soul Drinkers Chapter is an exception, as they still believe themselves to be loyal servants of the Emperor, and continue to defend the Imperium, even though they are no longer part of it.

Young psykers who have not worked against the Imperium or used their powers much will usually be repeatedly tested, and if they are young, strong and pious enough, may be taken in by the Black Ships of the Inquisition to become a Sanctioned Psyker or even an Inquisitor. The requirements are strict and many will be found wanting. Those that fail the Inquisition's tests will either be executed or used to power the vast psychic beacon of the Astronomican, their lives sacrificed for the ultimate good of Mankind to sustain the Golden Throne which keeps the Emperor alive.

If a world is the subject of extreme corruption by Chaos, an Inquisitor may call down the verdict of Exterminatus, destroying all ecosystems on the planet and rendering the world completely lifeless. Many question the necessity of such acts, but the Inquisition feels fully justified in performing them. They feel that it is better for countless servants of the Emperor to be sacrificed than to let a single heretic escape their wrath to endanger more lives. Typically, though, such an act is reserved for only the most extreme cases, such as a massive outbreak of Chaos activity that threatens to corrupt other worlds or unchecked infiltration by Genestealer Cults that precede (or can cause) a Tyranid invasion that will consume an entire sector.

Organisation
The Inquisition does not have a formal organisation and is, at the most fundamental level, dependent upon the authority and skill of the single Inquisitor and his team of Acolytes and Throne Agents. Every Inquisitor embodies the whole Inquisition and is granted the same absolute power by virtue of the Inquisitorial Mandate. As the word of an Inquisitor is absolute and beyond reproach, except by other Inquisitors, the Inquisition is self-policing. At one time it was said that the Ordo Malleus was responsible for policing the Inquisition, however this idea seems to have been abandoned and there are now those within each of the Ordos who focus their time in purging the Inquisition of rogue elements; the Ordo Hereticus is particularly noted for having members who keep a close eye on fellow members of the Inquisition. Despite the lack of a formal organisational structure, there are many types of Inquisitorial groupings that an Inquisitor may belong to, however membership within these is not mandatory. For example, an Inquisitor may choose not to join an Ordo, however by not doing so he will be unable to access their resources. Similarly, an Inquisitor is expected to announce his presence to the head of the Conclave overseeing the sector or region of the galaxy in which he operates, however many Inquisitors prefer to work in secret.
 * Conclaves - Inquisitorial Conclaves can be split into two rough groups. The first are Conclaves called by an Inquisitor (or High Conclaves called by an Inquisitor Lord); these are gatherings called to discuss a particular subject. There are also more permanent regional Conclaves; these are federations of Inquisitors who watch over a particular area or sector of Imperial space. The larger of these regional Conclaves may have resources such as starships, armies, fortresses and libraries for the use of their members. Not all sectors of Imperial space are covered by a Conclave, and some areas are devoid of a permanent Inquisitorial presence. The head of each regional Conclave is normally an Inquisitor Lord, and is nominally appointed by the High Lords of Terra. There are also Conclaves operating at the Segmentum level, again headed by an Inquisitor Lord.
 * Cabals - A Cabal is a rare body instituted by a Conclave and dedicated to investigating a particular matter. They form a specialist task-force charged with the prosecution of a particular concern. Generally they gather Inquisitors from varied backgrounds and philosophies, all working together via their differing methods and focused on a single goal. All too often, Cabals are despised by many who see them as secret societies within a Conclave.
 * Factions - The various Inquisitorial factions are groups of Inquisitors who share the same philosophical proclivities concernign the future direction of the Imperium. Factions can be divided into two rough groups, Puritans and Radicals. Puritan factions include the Monodominants, Amalathians and Thorians who tend to uphold the letter of Imperial law and the dictates of the Emperor, with no room for reinterpretation. Radical factions, such as the Xanthites, Recongregators and Istvaanians, feel they are free to enforce the spirit and intent of the Emperor’s judgements, and for them the end really does justify the means.

Inquisition Hierarchy
The Inquisition does not have a formal hierarchy, and there is no system of ranks or command such as is found in the Imperial military or the Adeptus Terra. Authority within the Inquisition is governed by two factors -- reputation and influence. Seniority is in itself no indicator of authority, however most Inquisitors will take heed of the wisdom of an older and more experienced peer.
 * Inquisitor Lords - Despite the lack of formal organisation, there is a need for a higher tier of Inquisitors to help maintain the integrity of the organisation, and to watch over and guide its members. They are known by various names including Inquisitor Lords, Lord Inquisitors and High Inquisitors. Inquisitor Lord (or one of its variations) is a recognition rather than an absolute rank, and is more a formalisation of a position of influence amongst his fellows enjoyed by the Inquisitor rather than an actual promotion. Promotion to the ranks of the Inquisitor Lords is by invitation only; an Inquisitor must be nominated by an existing Lord and have his nomination approved by two others. It is an honour that is only extended to those that have proven their courage, ability, loyalty and integrity numerous times. Although the rank of Inquisitor Lord in itself brings no temporal authority, it is likely that such a respected and influential Inquisitor will have some measure of control over resources within the Inquisition or his Ordo and his control of those resources will give him some measure of authority over Inquisitors who wish to use them.
 * Grandmaster - Grandmaster is a title sometimes given to an Inquisitor Lord who runs a sector or sub-sector Conclave, such as Lord Orsini, Grandmaster of the Ordos Helican.
 * Master - Where an Ordo has a strong presence in a sector or sub-sector, the senior Inquisitor Lord of each Ordo may be given the title "Master." In the Ordos Helican, there are three Masters, one for each of the Ordos Majoris; who as well as overseeing the members of their Ordos also provide counsel to the Grandmaster and are responsible for choosing his successor should he die or retire.
 * Inquisitorial Representative - The Inquisitorial Representative is the voice of the Inquisition on the Senatorum Imperialis. Although the role does not bring any additional authority above that of a standard Inquisitor Lord, it does put the holder in a position of unrivalled power and authority due to the influence he has at the highest levels of Imperial power. The Inquisitorial Representative is nominated from amongst the Inquisitor Lords of the sectors surrounding Terra, and Inquisitors that have filled this role are referred to as an Inquisitor Lord Terran. Also, it is not unusual for several Inquisitor Lords Terran to share the role of Inquisitorial Representative at the same time. The maximum term that an Inquisitor Lord Terran can serve on the Senatorum Imperialis is five standard years, after which they must stand down -- though nothing prevents them from eventually serving another five-year term.

Operations
The basic unit of the Inquisition is the individual Inquisitor with his or her retinue of Interrogators, Acolytes and Throne Agents. Each Inquisitor travels the Imperium as his duties, studies, interests and local events direct him, and seeks out threats to the Imperium wherever he goes. When one is found, the Inquisitor will usually deal with it personally if his resources permit. If they do not, the authority of the Inquisition allows him to bypass the often unwieldy Imperial power structures that would hinder effective halting of such a threat by directly requisitioning military force from the Imperial Guard, the Adeptus Astartes, the Sisters of Battle of the Adepta Sororitas, the Officio Assassinorum or whatever else may be required, and applying them where needed. However, the Inquisition also organises itself across the Imperium on a more permanent basis in sector-wide units called Conclaves. For instance, all the Inquisitors, Inquisitorial agents and Inquisitorial fortresses within the Calixis Sector of the Segmentum Obscurus are considered part of the Calixian Conclave.

Inquisitors can move between Conclaves as their work requires, and each Conclave can be composed of Inquisitors from any of the three major Ordos and some of the more minor regional Ordos as well. Almost every sector in the Imperium has an Inquisitorial Conclave, though some sectors, such as those in the Segmentum Obscurus that lie on the border of the Eye of Terror like the Calixis Sextor, possess Conclaves containing hundreds of different Inquisitors. Other sectors where the threat level is lower may have Conclaves populated by only a few or even one Inquisitor and his retinue at a time. Each Conclave is usually headed by a very senior Inquisitor Lord with hundreds of Terran years of service to the Emperor under his or her belt, though some of the larger Conclaves are led by a secretive council of the most powerful Inquisitor Lords operating in that sector.

To allow Inquisitors to operate as needed across the Imperium safely and without abuse of their immense and open-ended authority, the Inquisition gives each appointed Inquisitor an Inquisitorial seal. This is an Inquisitorial rosette, signet ring or similar adornment bearing the Inquisitorial icon, and gives the bearer all the potent political powers of the Inquisition, including the authority to requisition Imperial Guard troops or Space Marines, call upon all 3 of the Chambers Militant of the Inquisition and more besides (usually claimed "by the authority of the Immortal Emperor of Mankind"). The seal doubles as a decoder for encrypted Imperial documents up to the highest levels of security clearance and may have similar other perks depending upon the individual Inquisitor's record of accomplishment. The crime of forging an Inquisitorial seal carries some of the worst punishments the Inquisition can call down on transgressors, which is saying something.

Occasionally a matter will surface that requires more lengthy study and debate than a normal Inquisitorial case. In such cases, Inquisitors may hold Apotropaic Studies. These Studies usually gather between two or three Inquisitors. Larger meetings known as Apotropaic Councils or Conclaves will gather at least eleven Inquisitors for debate and study of an important issue, or they may be called to ensure communication within the members of a faction or philosophical grouping of the Inquisition. Quite rarely, a so-called "High Conclave" or Apotropaic Congress may be convened, but only by an Inquisitor Lord. These will often gather dozens of Inquisitors for weeks of debate on many related topics. Usually, it is at Conclaves and meetings of this sort that new Inquisitors will be appointed. It is also during such meetings that the Inquisition polices its own ranks, as no other organisation in the Imperium has the authority to do so.

Inquisitors with a certain degree of seniority (usually several decades of field experience) will often take on apprentices from various sources. These apprentices are called Interrogators, though there are several other ranks of Inquisitorial apprenticeship. When his master deems him ready, an apprentice Inquisitor may be elevated to the rank of full Inquisitor. Normally, this requires the consent of at least three other Inquisitors or an Inquisitor Lord, but in extraordinary circumstances, such as the untimely death of his master, an apprentice may become an Inquisitor without these formal approvals.

Very senior Inquisitors with several decades or even centuries of service may become Inquisitor Lords. This largely honorific rank is bestowed by invitation from an existing Lord only, and requires the approval of two other Inquisitor Lords to be officially bestowed. The latter requirement is largely a formality, however, as Lords are few and far between in Imperial space and the odds of one Inquisitor being personally known to more than one is vanishingly small. Inquisitor Lords have a few extra powers within the Inquisition itself, but the title is mostly an acknowledgement of extraordinary service to the Emperor and the senior position they have earned within the Inquisition through long years of service.

Part of the nature of the Inquisition's work requires numerous undercover operations (depending on the individual Inquisitor, of course). Particularly dangerous or sensitive missions may require the Inquisitor and his crew of Acolytes to operate without even the remit or knowledge of local planetary authorities; in some cases, the Inquisitor may fake the deaths of themselves and their Acolytes in order to move their mission forward invisibly. At times like this, Inquisitors operate under a mandate known as Special Condition, which means that the Inquisitorial team, to all intents and purposes, no longer exists. The normal Inquisitorial symbol of office is replaced with a somewhat altered symbol during Special Condition missions that has a dagger-like point at the end and is colored a distinct blue shade, with a winged skull prominent near the top of the sigil; it is presented only when recruiting members to the team who can be trusted not to jeopardize the secrecy of the mission. Eisenhorn and Ravenor are two of the most famous Inquisitors to have gone on Special Condition.

Inquisitorial Retinues
Often experienced Inquisitors or ones in need of specific services depending on their Ordo or the current situation at hand will have retinues of henchmen that he has deemed most useful. These retinues can be made up of a variety of individuals from Chirurgeon medics to lobotomised Gun Servitors carrying massive heavy weapons. The full list of known Inquisitor henchmen is described below:
 * Acolytes - Interrogator/Explicator: An Inquisitor can take on apprentices and teach them everything he knows so that they too can some day become full Inquisitors like their master.
 * Chirurgeons - Torturer/Excoriator/Sister Hospitaller: Members of the Adepta Sororitas' Orders Hospitaller or just those individuals trained in torture, interrogation and punishment, they can aid an Inquisitor in interrogating prisoners or healing wounds done to the Inquisitor and his Acolytes in battle.
 * Familiars - Cherubim/Servo-skull/Psyber-Eagle: By far the strangest of henchmen, familiars boost the psychic prowess of psyker Inquisitors and allow him greater initiative. (N.B.: In Inquisitor game terms, these would normally be considered as part of a character's equipment, not as a member of the warband.)
 * Hierophant - Castigator/Ecclesiarchy Priest/Exorcist: Fiery members of the Ecclesiarchy, they boost the faith of the Daemonhunters they are in service to and chant exorcisms and prayers that can cause agony to nearby daemons.
 * Mystics - Astropath/Warp-Seer/Sanctioned Psyker: Sanctioned psykers used by the Inquisition to detect the presence of daemonic creatures.
 * Penitent - Bound Psyker/Penitent Witch/Pariah: When a Witch Hunter makes a heretic psyker repent his sins (a notably rare event), he could become what could be called a "psychic lightning rod", absorbing the psychic attacks of other heretic psykers and protecting the Inquisitor and his retinue in battle.
 * Sage - Autosavant/Lexmechanic/Calculus Logi: Individuals whose mathematical skills are so keen that they can calculate firing angles and trajectories perfectly, increasing the chance for an Inquisitor's ranged weaponry to hit its mark.
 * Warrior - Imperial Guard Veteran/Combat-Servitor/Gun-Servitor/Crusader/Adeptus Arbites Arbitrator: These individuals (or mindless automatons in the case of the Servitors) act as bodyguards and combat support for Inquisitors and serve their master in direct, physical combat against the minions of Chaos.
 * Untouchables - Inquisitors may also bring in an Untouchable, a psychic Blank who possesses the anti-psyker Pariah Gene, to counter detection from that of another psyker or a group of psykers. Normally an Untouchable does little more than serve as a "tourist" who follows the Inquisitor. Use of Untouchables in the Inquisition was first introduced by Inquisitor Gregor Eisenhorn who, after finding an Untouchable, helped form a distaff because of their usefulness against the many powerful psykers the Inquisition encounters. This distaff was ultimately attacked and destroyed by the Heretic Pontius Glaw, but Untouchables have continued to be used in Inquisitorial retinues after their underrated ability saved Inquisitor Eisenhorn many times. Some examples of Untouchables prominent in the Warhammer 40,000 universe include Wystan Frauka of Gideon Ravenor's retinue, and Jurgen, who was a part of the retinue of Commissar Ciaphas Cain.

Especially helpful, competent (or attractive) retainers may become permanent members of an Inquisitor's retinue as new Acolytes, helping him bring light to the dark corners of the galaxy. Note that this list is not exhaustive as many different kinds of individuals with many different personalities and jobs have been seen in the employ of Inquisitors in fiction. This allows for Inquisitorial retinues and the Inquisitors themselves to be highly distinct models with different personalities, weapons, histories and attitudes.

Philosophical Sects
The Inquisition's members broadly adhere to two very different schools of thought about their ultimate purpose and the methods to be used in pursuit of that purpose; that of the Radical and that of the Puritan. To the Radical "the ends justifies the means" in every instance, whether through the employ of Exterminatus, Daemonhosts, or alien weaponry. By contrast, the Puritans adhere strictly to official Imperial political and religious doctrine and typically persecute their more unorthodox brethren when given the chance, as they are most concerned with maintaining the Imperium's status quo, even if this results in simply perpetuating the long period of technological and cultural stagnation that has afflicted Mankind since the end of the Horus Heresy over ten millennia ago. The main tenets of the Inquisition's competing philosophical sects on how best to defend the Imperium, beyond the basic Radical/Puritan divide, can be defined below:

Puritans

 * Thorianism - Born of the fire and ruin of the Age of Apostasy in the 36th Millennium, the Thorian Inquisitors are a Puritan faction who believe that the will of the Emperor can manifest in the hearts of pure men and in times of great need his avatar will appear to vanquish the foes of humanity. They take their name from the great prophet and leader of the 36th Millennium, Sebastian Thor who, during that dark time, led the movement against the corruption within the Imperial Cult and was ultimately responsible for its cleansing and the restoration of the Imperium that followed. This is the most "Radical" of the Puritan ideologies due to the possible galactic upheaval that could result should the Thorians actually be able to summon the Emperor into a new physical form, as believers and unbelievers in the reborn Emperor's divinity and identity then turn upon each other.
 * Monodominance - Next to the Thorians, the Monodominants are counted among the most powerful of the Inquisitorial factions. Certainly this Puritan faction is believed to be the oldest, tracing its origins back to a time shortly after the creation of the Inquisition itself sometime in the 33rd Millennium. Monodominants are the most hard-line of all the Puritans, believing in the complete destruction of all non-humans (including mutants and psykers) and those not willing to swear eternal allegiance to the Emperor. Of course, they understand that this lofty goal will take time and, in the interim, though they might despise them, the Imperium must make use of mutants and psykers for its survival. Monodominants are also well known for their excessive use of force when purging corrupted worlds, even resorting to Exterminatus rather than risk leaving even the barest hint of heresy behind.
 * Amalathianism - The conservative philosophy that dominates the Puritan faction of the Inquisition, an Amalathian advocates for unity between Imperial organisations in the pursuit of the Emperor's will and for a lack of tumultuous social and political change to maintain the Imperial status quo. The Amalathians are thus the currently largest sect within the Inquisition. Amalathian Inquisitors oppose the Inquisition's division into political and philosophical factions and sects. Ironically, their idealism marks the Amalathians as their own faction in the Inquisition. It was at the birth of this philosophy, on the world of Gathalamor, at Mount Amalath, that Lord Solar Macharius was spurred on to his grand conquest of nearly a thousand new worlds for the Imperium during what became known as the Macharian Crusade.

Radicals

 * Xanthism - The most powerful and obviously Radical grouping within the Inquisition, Xanthites advocate the use of Warp-based weaponry, such as daemon-possessed swords, Daemonhosts, and other tactics that will turn the power of Chaos against itself. Xanthism is named after Inquisitor-Master Zaranchek Xanthus, who was executed in the 32nd Millennium as a Heretic for reputedly possessing a dangerous and unhealthy amount of knowledge of the Warp and its uses. Note that, unlike other Inquisitors, only the rare openly Xanthite Inquisitors will be denied the use of the Grey Knights if they requisition them. Xanthites are considered too impure themselves to be given comand of the Grey Knights; more Puritan Inquisitors fear that they may actually be leading those elite Space Marines into a trap in service to the powers of the Warp, whether they realise it or not.
 * Horusians - A sub-sect of the Xanthites, this sect wishes to create a new leader for humanity, much like the Puritan Thorians. Both factions strive for a powerful, god-like figurehead to lead the Imperium into a new golden age. But the Horusians view the might of Horus as a wasted opportunity; they believe that should the limitless power of Chaos be harnessed and bound into a great leader of men, humanity could once more become united and crush all before it. Needless to say, even other open-minded Radical members of the Inquisition view the Horusians as dangerous in the extreme, likely to become nothing more than more traitorous pawns of the Ruinous Powers.
 * Recongregationism - The Recongregators believe that the Imperium, after long millennia of stagnation, has become decadent and corrupt. To remedy this, Recongregators believe that only through change can the Imperium hope to prosper, believing that the greatest threat that humanity faces is its lack of progress and terminal stagnation. Working quietly behind the scenes, the Recongregators seek to influence or engineer events that will lead to change and progress. It is a subtle game, and of all the major factions of the Inquisition, they are counted amongst the least visible, keeping to the shadows whilst others charge into the fray. They are most deeply opposed within the Inquisition by the Puritan Amalathians.
 * Istvaanism - Even more extreme in their views than the Recongregators is the Radical faction known as the Isstvanians. Taking their name from the infamous massacre on Istvaan III, where Horus virus-bombed the remaining Loyalist Space Marines in his Traitor Legions, said to have been the spark that ignited the Horus Heresy, they seek to ferment conflict and crisis wherever they tread. It is their belief that the Imperium requires constant strife to survive (a reasonable assumption given the galaxy's state of near total war), and if Mankind were ever to find itself at total peace, the Imperium would collapse and decay. To this end, Istvaanian Inquisitors seek conflict head-on, instigating discord within and without the Imperium, starting wars, leading invasions, and stirring discontent into rebellion.

Calixian Factions
In addition to the six most well known factions described above, scores of others are whispered to exist across the Imperium. These are rumoured to be splinter groups of the larger factions, fractured from their parents by extreme views or differing beliefs, such as the Puranthius or Antus-psykeer who seek to cleanse the Imperium by targeting specific foes or practices. Alternatively, they may be a result of local phenomena, such as the Clavianus of the Eastern Fringe, dedicated to the understanding the unique philosophies of the Tau. In the Calixis Sector, there are several of these splinter factions. Some are mere shadows of greater schools of belief, while others are genuine organisations in their own right, with no small amount of power and influence within the boundaries of the sector. These factions include:
 * Xeno Hybris - The Xeno Hybris is a Radical faction that has existed within the Calixis Sector for almost as long as it has been a part of the Imperium. It is speculated that the faction grew out of a gathering of Radical Ordo Xenos Inquisitors and agents drawn to the sector in search of clues to lost alien civilizations. Whatever the case, today the faction works diligently to uncover alien technology and better understand the alien mind. Inquisitors of this faction believe that there is much to learn from the aliens of the galaxy and only by cooperation with the other intelligent starfaring races can the true enemy of all sentient life be defeated. Needless to say, these beliefs often bring them into conflict with Monodominants and their followers, who view any dealing with xenos as an abomination.
 * Seculos Attendous - As yet, this faction has remained very quiet about its intentions and goals, no doubt to avoid immediate censure and the risk of excommunication. They view the superstitious dogma and religious doctrine of the Adeptus Ministorum and the Imperial Cult to be slowly corrupting Mankind and hampering its growth, pointing to the Age of Apostasy and the reign of the tyrant High Lord Goge Vandire in the 36th Millennium as proof of this. They seek to undermine the influence of the Ecclesiarchy and slowly weaken the power of the Imperial Cult over the minds of the Imperium's masses, hoping to restore the more secular orientation of the Imperium that once characterised what was known as the Imperial Truth before the outbreak of the Horus Heresy. For obvious reasons, this sect of the Inquisition is bitterly opposed by the Adeptus Ministorum and its many agents.
 * Polypsykana - An offshoot of the Xanthites, the Polypsykana is a Radical faction obsessed with the power of psykers. Members believe that the psyker is a natural evolution of man's development into a higher being. After all, the Emperor is the greatest psyker of all, who keeps the Imperium intact through His immeasurable strength of will, even guiding ships safely through the Warp by igniting the blazing beacon known as the Astronomican. The faction believes that this transformation of humanity is inevitable and ultimately Mankind's only salvation. To this end, members work to protect and nurture psykers and increase the role they play within the sector. In addition, they work in secret on psy-tech, psy-breeding and other, more questionable, activities, all intended to spread what they see as the psy-gene to as much of humanity as possible.

Notable Inquisitors

 * Agmar - As a young member of the Ordo Hereticus, he lead multiple attacks upon Ichar IV's capital city of Lomas to break up rebellion among strange cult members. It turned out that the rebellion was created by a massive Genestealer infestation. With the Adeptus Arbites, he destroyed enough defenses to allow the Ultramarines Chapter to seize the planet. It was then that Angmar's Astropaths felt the approach of Hive Fleet Kraken and it was his initiative that led to the breaking of the Hive Fleet at Ichar IV.
 * Ario Barzano - Member of the Ordo Xenos. Barzano disguised himself as an Adept of the Administratum on the planet Pavonis in order to help the Ultramarines stop the awakening of the C'tan called the Nightbringer. He dies in the attempt and is buried on Pavonis.
 * Covenant - One of a new breed of Daemonhunters who hunts down traitorous members of the Inquisition itself and their Daemonhosts. He trained the Inquisitor Ivixia Dannica. Covenant is equipped with a Power Falchion, a Psycannon and limited psychic powers.
 * Torquemada Coteaz - An Inquisitor Lord of the Ordo Malleus and High Protector of the Formosa Sector, a title he took from Inquisitor Laredian when it was revealed that Laredian created Daemonhosts and other abominations. Coteaz is an infamous adversary and destroyer of daemons; his name is a reference to the medieval Spanish Inquisition leader Tomás de Torquemada.
 * Bronislaw Czevak - One of the few non-Eldar to gain access to the infamous Black Library. Bronislaw Czevak reported the destruction caused against the Eldar Craftworld Iyanden and its supporting spacefleet by the Tyranids.
 * Daemonhuntress Ivixia Dannica - After her father Colonel Dannica was murdered by a daemon summoned by cultists who wanted revenge for the purge he enacted on them and their brethren, Ivixia was trained by Covenant. She had her father's skull fitted with an autogun and fitted to her armour so he could serve the Emperor beyond death. She wields a Power Halberd made from the shards of Saint Josmane's armour. The weapon is filled with the power of the saint and has sent scores of daemons screaming back to the depths of the Warp.
 * Jaq Draco - Jaq Draco was a secret Inquisitor of the Ordo Malleus, active in the late 38th and early 39th Millennia. He purportedly uncovered a widespread conspiracy involving numerous high-ranking members of the Inquisition known as the Ordo Hydra, as well as highly sensitive information regarding the Emperor. Draco proved instrumental in stopping a plot by the Ordo Hydra to psychically enslave Mankind in the hope of striking a blow that would eliminate Chaos from the galaxy forever. In reality, the plan very likely would have spawned a fifth Chaos God who would have guaranteed the ultimate victory of Chaos over the Imperium of Man. In the course of his mission Jaq Draco became one of the few individuals in the galaxy to have entered the Emperor's Sanctum Imperialis to have an audience with the Emperor of Mankind since his internment in the Golden Throne at the end of the Horus Heresy. It is also said that he was the only human to ever penetrate the fabled Black Library, their secret Craftworld within the Webway, that contains the entire race's knowledge concerning Chaos, without the Eldar's consent. He was declared Renegade by the Inquisition, and he was reported to have died within the Webway in the early 39th Millennium under mysterious circumstances. Draco was known to have a retinue consisting of a Navigator, an Assassin and a Squat. He was reported to be a formidable Psyker.
 * Gregor Eisenhorn - An Amalathian member of the Ordo Xenos, Eisenhorn was the infamous Inquisitor who orchestrated the downfall of Quixos the Bright and Pontius Glaw using a stolen daemonhost named Cherubael, a former tool of Quixos. He seemingly vanished soon after the downfall of Pontius Glaw. Eisenhorn changed over the course of his career from being a staunch Puritan Amalathian into a Radical Inquisitor through the justified choices he made. These choices included keeping the Malus Codicium for himself, and trying to save his comrades from the attack of Cruor Vult (a Chaos Warhound-class Scout Titan) by summoning Cherubael. Gregor also caused the downfall of many other foes, including Beldame Sadia, Mandragore, the House of Glaw, Cruor Vult, and the rogue Inquisitors Lyko, Molitor and Quixos.
 * Silas Hand - Silas Hand is an important character of Daemonifuge, a graphic novel by Kev Walker. He was first a Witch Hunter serving under the Ordos Solar and eliminated thousands of heretics. After being approached by an important Daemonhunter, Inquisitor Lord Hephaestos Grudd, he was invited and joined the Ordo Malleus. Inquisitor Hand was sent to Ophelia VII to identify if Ephrael Stern was tainted by Chaos. Mysteriously, she was the sole survivor out of 12,000 Imperial Guardsmen that were sent to the planet Parnis. His investigation led to no conclusion, and Hand was forced to return with her to the planet Parnis. During the return, their vessel's Navigator was possessed by Chaos and destroyed their starship the Hammer of Thor. Escaping, both Hand and Stern were able to land upon the surface. However, they soon confronted the Daemon Q'tlahsi'issho'akshami. Only Stern managed to live through the battle.
 * Jason Hunt - Ordo Malleus Inquisitor and Warden of the Stromgard Sector. Hunt is closely affiliated with Commander Marcus Flintlock of the Storm Dragons Space Marines, and has used detachments of that force frequently in pursuit of his missions. He is also a high-level psyker.
 * Lady Helena Jerico - An Ordo Xenos Inquisitor. She has had numerous dealings on the planet Necromunda. Mother of bounty hunter Kal Jerico.
 * Fyodor Karamazov - An Inquisitor Lord of the Ordo Hereticus, also known as the Pyrophant Judge of Salem Proctor. This is a reference to Arthur Miller's "The Crucible," Proctor being the name of one convicted, yet innocent, witch; and Salem being the Puritan township he lived in. A staunch Amalathian, Karamazov habitually judges and does battle from his massive Throne of Judgement and is generally hated by the Ecclesiarchy and Thorian Inquisitors for his actions on Salem Proctor. His name is a reference to Fyodor Dostoevsky, Russian author of the novel "The Brothers Karamazov," which contains a parable entitled "The Grand Inquisitor." Karamazov made the infamous quote that is used to sum up an Inquisitorial investigation: "There is no such thing as a plea of innocence in my court. A plea of innocence is guilty of wasting my time."
 * Kryptman - Member of the Ordo Xenos, Tyranid expert, saviour of the Imperium in the Hive Fleet Leviathan crisis, and the discoverer of a full 82 new alien species (all of which he subsequently deemed a threat to the Imperium and ordered eradicated). Kryptman was the first Inquisitor to witness the devastating effects of a Tyranid invasion during the attack of Hive Fleet Behemoth and fought the Tyranids for over 250 years. He was one of the most active members of the Inquisition against the Tyranid invasions, even taking drastic measures to the dismay of other Inquisitors. During the Invasion of Hive Fleet Leviathan, Kryptman led Deathwatch kill-teams to the Tarsis Sector to aid the Mortifactors Chapter and the Ultramarines of Tarsis Ultra. By capturing a Lictor, Magos Biologis Locard (Kryptman's Adeptus Mechanicus biologist) created a biological weapon to use against the Tyranids and his Deathwatch members used it to destroy the Norn Queen. Kryptman later authorised the largest single act of genocide the Imperium has ever inflicted on itself by abandoning or destroying all worlds in Hive Fleet Leviathan's path. He was later issued a "Carta Extremis" and was stripped of his title. However, this did not stop him and he soon led his loyal Deathwatch warriors to steal Genestealers in stasis and used them to lure Tyranids to the homeworlds of the Orks of Octavius.
 * Ligea - Inquisitor Ligea can be described as "Looking more like an elegant family matriarch rather than a hunter of daemons." Ligea was an unusual Inquisitor, in that she did not see much combat, but rather focused her efforts on texts and ancient writing. She possessed at least one minor psyker ability, which allowed her to apprehend information simply by contacting an object, such as a book or a statue. She was recruited into the Ordo Hereticus at a very young age. One of her most notable parts was in the novel "Grey Knights" by Ben Counter, which tells the tale of Ligea, and how she was attached to the Grey Knights Chapter on the trail of Saint Evisser, looking for Ghargatuloth, Prince of a Thousand Faces, a powerful Greater Daemon of Tzeentch. Unfortunately, Inquisitor Ligea eventually succumbed to the taint of Ghargatuloth after allowing herself to delve too deeply into tainted knowledge, opening her mind to Daemons which caused her to lose her mind. Having gone quite insane and fallen mostly to Chaos in the process, Ligea was captured by the Inquisition she once served. However, having opened herself up to Ghargatuloth, she was able to learn and reveal the true name of Ghargatuloth to Justicar Alaric, through a recording of her interrogations, in which she babbled what was apparently a meaningless string of syllables. This gave the Grey Knights the advantage they needed in order to destroy Ghargatuloth once every thousand years. Inquisitor Ligea died in an interrogation room high above the planet Mimas when Inquisitor Nyxos ordered her cell opened, venting her into space.
 * Solomon Lok - Member of the Ordo Xenos, Solomon Lok lead the investigation of the loss in communication from Beta Anphelion IV, supported by Space Marines from the Red Scorpions Chapter, along with Imperial Guard troops from the Elysian Drop Troops Regiment D-99, and also a regiment from the Cadian Shock Troops. Featured in "Imperial Armour IV," and one of the few Inquisitor models cast by Forge World.
 * Lady Jena Orechiel - The daughter of an Imperial Governor and member of the Ordo Xenos, Jena is currently investigating the supposed reawakening of the C'tan. Jena is a character in the game "Inquisitor."
 * Gideon Ravenor - Previously an Acolyte to Gregor Eisenhorn, a more powerful psyker than even Eisenhorn himself, and author of many famous texts such as the 'Spheres of Longing'. Gideon Ravenor's early career saw him in action with Gregor Eisenhorn and together they brought down many heretics, most notably the Beldame Sadia - an accursed cybernetically-enhanced xenophile. During the Triumph under the Spacian Gate (a large parade to celebrate the Warmaster's victorious purge of the Ophidian Sub-sector) Ravenor is caught on the edge of an explosion caused by a crashing Lightning Attack Fighter. He is rendered Blind, Deaf, Mute, and senseless. Were it not for his genius and Psychic potential it would have been the end of the finest Interrogator Eisenhorn ever raised. He has been encased in a mobile life support system that serves as his protector as well as amplifying his already considerable psychic abilities. He communicates through telepathy with members of his retinue.
 * Reynaard - Reynaard discovered a cult worshipping aliens on Mandall IV. Using a Deathwatch kill team, he attempted to destroy the cult, which proved to have taken over most of the capital city. After escaping, Reynaard returned with over 500,000 troops and eradicated all in the city.
 * Scarn - A very secretive Inquisitor who avoids combat at all costs, and is instead a master manipulator. Last seen at an Inquisitorial Conclave six decades previously. For the past sixty years he has been working his ultimate plan, which he believes will solve all the problems that the Imperium faces, and only now are the pieces in place for stage one. Scarn was featured in the Inquisitor Campaign Supplements.
 * Thaddeus - An Inquisitor of the Ordo Hereticus, he was put in charge of hunting down and destroying the renegade Soul Drinkers Space Marine Chapter. He is a rather patient man and does things slowly and concise as to do them right. He shuns other Inquisitors who use force and fear on Imperial citizens to get their information. He believes in speaking to people politely and with respect to get what he needs. He seemed to make a deal with Sarpedon, the acting Chapter Master of the Soul Drinkers, when Sarpedon was injured badly and held almost in death by an insanely powerful mutant attempting to gain godhood in the Warp, known as Teturact. Thaddeus decided to spare Sarpedon after months of trailing the Soul Drinkers and fired on Teturact, giving Sarpedon time to finish him with the Soulspear. Thaddeus decided that Sarpedon wasn't nearly as dangerous to the Imperium as Teturact was. Thaddeus fell out of favour with the Lord Inquisitors for allowing the Soul Drinkers to continue to exist, but he still pursued them and eventually met his end facing down the Howling Griffons Space Marines after being seen as Sarpedon's ally.
 * Mordecai Toth - Mordecai Toth was featured in the Dawn of War real-time strategy game. Wielder of the Daemonhammer "God-splitter," crafted from a fragment of the weapon of an Eldar Avatar of Khaine, which he later gifted to the Blood Ravens Chapter. In the Dawn of War novel series, he reclaims the "God-splitter" from the Blood Ravens, and is portrayed as a probable agent of Tzeentch, the Chaos God of Change. Toth tricked Blood Raven Captain Gabriel Angelos into freeing a powerful Daemon imprisoned by the Eldar.
 * Tyrus - A staunch Monodominant and hunter of all psykers, who wears elaborate ornate power armour. Witchhunter Tyrus is suspicious of witches and psykers. He personally wants to kill them all, human or not.
 * Amberly Vail - Member of the Ordo Xenos. Featured in the Ciaphas Cain series, she acts as the editor of the Cain Archive. It has been suggested that her relationship with Cain is more than professional.
 * Commodus Voke - Commodus Voke was an ancient and famous Thorian leaning towards Monodominant save for his very powerful psychic abilities. Lived to be extremely old due to being extremely difficult to kill. Arrogant and open with his position and fame, he was a sometime ally of Eisenhorn. A legend during his time, a testament to his ability, is the fact that he fought an uncontained daemonhost in a psychic duel and was not obliterated outright.