The Orders of the Emperor's @Holy Inquisition more commonly known as the Inquisition, are the powerful secret police of the Imperium responsible for guarding the souls of humanity. The purpose of the Inquisition is to identify and destroy the myriad of potential threats to the Imperium and humanity. Such is the Inquisition's power that it answers only to the Emperor.
The organization of the Inquisition is byzantine and consists of several overlapping structures:
Ordos are a major operational subfaction within the Imperial Inquisition. As the Inquisition possesses neither a formalized hierarchy nor leadership, each Inquisitor is free to pursue the mission of humanity's survival in the manner they see most appropriate. Like-minded individuals gather together to investigate areas of mutual interest and concern, as bounded by one of the many Inquisitorial Ordos. Each Ordo comes and goes with the times, for many Inquisitors move freely between them according to their own whims and judgement. Ordos can grow larger in crises and then exist only on paper until its field becomes relevant once more. Association with an Ordo is not a matter of absolute allegiance, nor does it preclude an Inquisitor's involvement in matters pertaining to another Ordo.[22b] As well as the Ordos, there are many types of Inquisitorial groupings that an Inquisitor may belong to, however, as with the Ordos, membership in these is not mandatory.[54a]
Conclaves - Inquisitorial Conclaves can take two forms. The first is a gathering called by an Inquisitor (if called by an Inquisitor Lord it is termed a "High Conclave") to discuss a particular subject.[18] There are also more permanent regional Conclaves; these are federations of Inquisitors who watch over a particular area of Imperial space.[7c] The larger of these regional Conclaves may have resources such as ships, 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.[8a]
Cabals - A Cabal is a rare body instituted by a Conclave and dedicated to investigating a particular matter. Generally they gather Inquisitors from varied backgrounds and philosophies to form a specialist task-force. Often, Cabals are despised by many who see them as secret societies within a Conclave.[7d]
Cells - Similar to a Cabal, a Cell is an ad-hoc group of Inquisitors who share a common goal. Often they are factional in nature, or are formed to confront a particular problem. The principle difference between Cabals and Cells is that the latter are entirely informal and are transitive in nature.[18] Often one or more of the Inquisitors in the Cell will work overtly through investigation while the rest proceed through infiltration[6].
Furthermore, on a philosophical basis the Inquisition is divided into various factions with disagreeing opinions on how the Inquisition should operate