The Inquisition — Warhammer 40k Secret Police

What Is the Inquisition?

The Inquisition is the most feared organisation in the Imperium of Man — a secretive body of individuals known as Inquisitors who hold almost unlimited authority to investigate, judge and execute anyone suspected of heresy, corruption or betrayal. In theory Inquisitors answer only to the Emperor himself (who sits silent on the Golden Throne), which places them outside the normal chain of command of every other Imperial institution, from the Space Marines and the Astra Militarum to the Adeptus Administratum.

The Inquisition’s roots lie in the Knights-Errant, the agents Malcador the Sigillite, the Emperor’s closest advisor, gathered during the Horus Heresy. Malcador died at the end of the Heresy, and the Inquisition itself was formally established in the aftermath as a watchdog that could act without bureaucratic constraint. Exactly who presided over its founding is deliberately obscure in the lore, and the Inquisition guards its own origins closely.

Ten thousand years later, the Inquisition is a vast, decentralised network of Inquisitors, each operating with tremendous autonomy. They maintain no standing army of their own but can requisition Imperial forces from any branch of the military, commandeer vessels from the Imperial Navy, and demand cooperation from any Imperial citizen or organisation. An Inquisitor’s authority is, in theory, absolute — challenged only by other Inquisitors.

The Three Major Ordos

The Inquisition is divided into numerous Ordos — specialised branches that focus on specific threats to the Imperium. Many minor Ordos exist, but three Major Ordos form the backbone of the Inquisition’s operations:

Ordo Hereticus — The Witch Hunters

The Ordo Hereticus hunts heretics, traitors and unsanctioned psykers within the Imperium itself. These Inquisitors investigate cults, root out Chaos corruption in Imperial organisations, and monitor the Adeptus Ministorum (the Imperial Church) for signs of deviation from approved doctrine. The Orders Militant of the Adepta Sororitas (Sisters of Battle) are traditionally described as the Ordo Hereticus’s Chamber Militant.

Ordo Hereticus Inquisitors are feared even by other Imperial institutions because their investigations can target anyone — planetary governors, military officers, Ecclesiarchy priests, and even other Inquisitors. Their methods range from subtle infiltration and intelligence gathering to dramatic purges that can see entire populations put to the torch if heresy is deemed too widespread to contain.

Some Inquisitors of this Ordo are measured investigators who carefully build cases before acting. Others are zealots who see heresy everywhere and respond with overwhelming force, destroying loyal citizens alongside genuine traitors.

Ordo Malleus — The Daemon Hunters

The Ordo Malleus specialises in combating the daemonic — entities from the warp that manifest in realspace to corrupt, destroy and consume. These Inquisitors study daemonology, warp phenomena and the nature of the Chaos Gods, using forbidden knowledge to fight an enemy that most Imperial citizens are not even permitted to know exists. The Grey Knights serve as the Ordo Malleus’s Chamber Militant.

Ordo Malleus Inquisitors investigate daemonic incursions, hunt down those who have made pacts with daemons, and work to contain warp-tainted artefacts. Their work frequently requires knowledge that is itself considered heretical — understanding how daemons function, learning the true names of daemonic entities, and studying how the warp interacts with reality.

This creates a tension within the Ordo. Some Inquisitors believe that knowledge of the daemonic is necessary to fight it, and will study or even use warp-related artefacts. Others insist that any contact with the daemonic is inherently corrupting and must be met with immediate destruction. The disagreement has, in several stories, turned rival Inquisitors against each other.

Ordo Xenos — The Alien Hunters

The Ordo Xenos focuses on threats from alien civilisations. These Inquisitors study xenos biology, technology and culture, seeking to understand alien species well enough to counter them. They monitor alien incursions into Imperial space, investigate reports of xenos influence on human worlds, and develop strategies for combating specific alien threats. The Deathwatch serves as the Ordo Xenos’s Chamber Militant, fielding kill teams of Space Marines seconded from many Chapters.

The Ordo Xenos deals with an enormous range of threats, from the Tyranid Hive Fleets to the T’au Empire to the ancient Aeldari. Ordo Xenos Inquisitors often specialise in a particular species, becoming experts whose knowledge is invaluable when that species threatens Imperial interests.

Radical members of the Ordo may advocate temporary alliances with certain alien species against greater threats, or the use of xenos technology. Puritans maintain that all aliens are enemies of humanity and that any cooperation with them is a betrayal of the Emperor’s vision.

Inquisitorial Powers and Authority

An Inquisitor’s authority is symbolised by the Inquisitorial rosette, which serves as both identification and a mark of near-absolute power. An Inquisitor bearing the rosette can commandeer Imperial resources, override local Imperial authorities, and pass judgement on any Imperial citizen, from the lowest hive worker to the most powerful planetary governor.

This authority extends to several specific powers that make Inquisitors among the most dangerous individuals in the Imperium:

Exterminatus: The most extreme sanction an Inquisitor can invoke. Exterminatus is the destruction of all life on a planet — typically through virus bombs, cyclonic torpedoes or sustained orbital bombardment. It is reserved for worlds deemed so thoroughly corrupted that no other remedy is possible. An Inquisitor who orders it without overwhelming justification can expect scrutiny from their peers.

Requisition: An Inquisitor can requisition forces from any branch of the Imperial military, including Space Marine Chapters (though Chapters may resist such demands). This allows a single Inquisitor to assemble a formidable force from whatever Imperial assets are in the region.

Judgement: An Inquisitor serves as investigator, prosecutor, judge and executioner. There is no appeal from an Inquisitor’s judgement, and sentences can range from exoneration to execution, mind-wiping or worse. This concentration of power is deliberate — the threats facing the Imperium are considered too urgent and too dangerous for normal judicial processes.

The Inquisitor’s Retinue

Inquisitors rarely operate alone. Each typically maintains a retinue of specialists, warriors and agents who assist with investigations and provide combat support. These retinues are as varied as the Inquisitors who assemble them.

Common retinue members include: Acolytes — agents in the Inquisitor’s service, some of whom are being groomed for higher things; Interrogators — senior apprentices being evaluated for elevation to full Inquisitor; Crusaders — dedicated warriors who serve as bodyguards; Mystics — sanctioned psykers; Savants — scholars and data-analysts; and Death Cult Assassins — fanatical killers devoted to the Emperor through obscure religious cults.

Some Inquisitors maintain large retinues that amount to small private armies. Others prefer a handful of trusted operatives, relying on subtlety rather than force. The most powerful can call on networks of agents spread across whole sectors.

Famous Inquisitors

The Inquisition’s history is filled with legendary figures:

Eisenhorn: Perhaps the most famous Inquisitor in Warhammer 40,000 fiction, Gregor Eisenhorn is an Ordo Xenos Inquisitor whose career spans centuries and demonstrates the Inquisition’s central philosophical conflict. Beginning as a committed Puritan, Eisenhorn gradually adopted Radical methods as he confronted increasingly dangerous threats, eventually using the tools of the enemy against it. Dan Abnett’s Eisenhorn novels explore how far a good person can go in fighting evil before becoming evil themselves.

Ravenor: Gideon Ravenor was Eisenhorn’s most talented student, an Inquisitor of exceptional psychic ability who was left crippled by the Thracian Primaris atrocity and continues his work from within a force chair — a levitating life-support system through which he projects his mind. His own trilogy, also by Dan Abnett, continues the themes of Eisenhorn’s from the perspective of a younger Inquisitor.

Karamazov: Lord Inquisitor Fyodor Karamazov is the embodiment of Puritan extremism. Riding a massive walking throne armed with a multi-melta, Karamazov travels the Imperium dispensing harsh judgement with zero tolerance for anything he deems heretical. He represents the Inquisition at its most uncompromising.

Coteaz: Inquisitor Lord Torquemada Coteaz is one of the best-known members of the Ordo Malleus, a veteran daemon hunter famed for his web of spies and informants. He fights alongside the Grey Knights and is one of the Inquisitors most often represented on the tabletop.

Puritans vs Radicals

The Inquisition’s greatest internal conflict is the philosophical divide between Puritans and Radicals — two opposing schools of thought on how best to protect the Imperium:

Puritans believe that the Imperium’s strength lies in strict adherence to Imperial doctrine and the total rejection of heretical tools, alien technology and warp-derived power. They view any compromise with the enemies of humanity as the first step towards damnation. Puritan Inquisitors destroy Chaos artefacts rather than study them, refuse to deal with aliens, and judge harshly anyone who deviates from approved Imperial behaviour.

Radicals believe that the threats facing the Imperium are too severe to be fought with orthodox methods alone. They advocate using every available tool — including forbidden knowledge, xenos technology and even daemonic artefacts — to protect humanity, and argue that refusing effective weapons against existential threats is not purity but stubbornness.

The conflict between Puritans and Radicals is not merely academic. Inquisitors have fought and killed each other over these differences. Neither side is entirely wrong — Puritans correctly identify that Radical methods carry genuine risks of corruption, while Radicals point out that Puritan rigidity can prevent effective responses to existential threats.

The Inquisition on the Tabletop

In Warhammer 40,000, Inquisitors are fielded through the Imperial Agents rules, either as their own army or as a small contingent alongside other Imperium forces. They are characters rather than front-line fighters: their value lies in their abilities and in the retinue units and Ordo-themed options that come with them, not in raw combat power.

In 11th Edition (launched June 2026) the existing Imperial Agents codex remains valid until a dedicated 11th Edition book replaces it, and armies are built with Detachment Points rather than a single detachment. Exact datasheets, points and detachment costs change with each Munitorum Field Manual, so check the current codex and the Warhammer 40,000 app before building a list.

Frequently Asked Questions

How powerful is an Inquisitor compared to a Space Marine?

In raw combat ability, most Inquisitors are inferior to Space Marines — they are still baseline humans (though often augmented with bionics, psychic powers and rare wargear). However, their political authority far exceeds any Space Marine’s. An Inquisitor can theoretically command a Space Marine Chapter to comply with their orders, though most Chapters would resist such demands.

Can an Inquisitor really destroy a planet?

Yes. An Inquisitor can order Exterminatus, the destruction of all life on a world. This extreme measure is reserved for planets deemed beyond saving — typically due to widespread daemonic corruption or an uncontrollable xenos infestation. Doing so without clear justification risks censure from other Inquisitors.

What are the three main Ordos of the Inquisition?

The three Major Ordos are: Ordo Hereticus (witch hunters who investigate internal heresy), Ordo Malleus (daemon hunters who combat warp entities), and Ordo Xenos (alien hunters who counter xenos threats). Each has a Chamber Militant: the Sisters of Battle, the Grey Knights and the Deathwatch respectively.

Who founded the Inquisition?

The Inquisition grew out of the Knights-Errant recruited by Malcador the Sigillite during the Horus Heresy, and was formally founded in the Heresy’s aftermath. Malcador himself did not live to see it — he died at the end of the Heresy — and the identities of those who actually established the Inquisition are kept deliberately vague in the lore.

What is the difference between a Puritan and a Radical Inquisitor?

Puritans adhere strictly to Imperial doctrine and reject the use of heretical tools, alien technology or warp-derived power. Radicals believe that extreme threats justify extreme methods, including the use of forbidden knowledge and enemy weapons. The conflict between these philosophies is the Inquisition’s greatest internal divide.

Can Inquisitors be corrupted by Chaos?

Yes. Despite their training and willpower, Inquisitors can fall to Chaos — especially Radicals who work with dangerous warp artefacts or forbidden knowledge. A fallen Inquisitor, with their knowledge and authority, is an extreme threat, and the Inquisition hunts its own renegades with particular urgency.

How do you become an Inquisitor?

Most Inquisitors start as Acolytes in another Inquisitor’s retinue, rise to Interrogator, and are elevated once their master and other senior Inquisitors judge them ready. They then receive the Inquisitorial rosette. There’s no formal school or exam, so the path depends entirely on sponsorship within the Inquisition.

Are there other Ordos besides the three major ones?

Yes. The Inquisition has many minor Ordos alongside the Ordo Hereticus, Malleus and Xenos. Known examples include the Ordo Sicarius, which liaises with the Officio Assassinorum, the Ordo Machinum, which watches the Adeptus Mechanicus, and the Ordo Sepulturum, which hunts plague and undead threats. Most are small and specialised.

What is an Inquisitor Lord?

An Inquisitor Lord is a senior, highly respected Inquisitor, such as Torquemada Coteaz or Fyodor Karamazov. The title reflects standing and influence, and Inquisitor Lords often lead conclaves of other Inquisitors. In theory every Inquisitor has the same authority, so rank matters more as reputation than as formal command.

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