Holy Ordos - Inquisition

As a completely autonomous Imperial organisation beyond the power of the Adeptus Terra, the Inquisition is immensely powerful. As the Inquisition's duties involve the scrutiny and policing of the other organisations of the Imperium, the Inquisition itself is answerable to no higher power except the Emperor. No one, except the Emperor himself, is beyond the scrutiny of the Inquisition. This power is officially known as the Inquisitorial Remit or Inquisitorial Mandate.
With the exception of the Ministorum (which, in any case is still under outside Imperial restrictions), the Inquisition is the only organisation of Imperial government that is completely autonomous. Unlike other Imperial organisations, it is not a branch of the massive Adeptus Terra, but a self-contained organisation answerable only to itself. The Inquisition itself uses compounds scattered throughout the Imperium known as Inquisitorial Fortresses as its bases of operation.²¹
The role of the ordinary Inquisitor is to investigate and deal with all potential threats to mankind and the Imperium. In the eyes of the Inquisition, there are multitudes of such potential threats. The main threat is posed not by invading aliens, but from within, by corruption and disloyalty within the Imperial organisations, as well as by psykers. The other threat posed from within is that of mutation, the constant corruption of the human gene-pool. There are no bounds to the Inquisition's area of responsibility: alien plots, mutation, political corruption, and incompetence all come under their jurisdiction².
If required, Inquisitors may call on the service and/or resources of any Imperial servant or organisation. Not even a High Lord of Terra may refuse the order of an Inquisitor without good reason. This power extends across the Adeptus Astartes and the Adeptus Mechanicus, however learned Inquisitors show discretion and request the assistance of the Space Marines and attempt not to anger the Adepts of Mars.
The role of the Inquisition requires proactivity and efficiency unbound by the dogmatic bureaucracy common to most other Imperial departments. Accordingly, there is little in the way of hierarchy or departmentalisation within the Inquisition. 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 an older and more experienced peer.^{10, 12}
Because the Inquisition are the watchdogs of the Imperium, answerable only to themselves, given almost absolute power, along with such broad jurisdiction, corruption is an ever present danger. Its integrity is therefore upheld by constant self-policing and scrutiny. In the earliest editions of the background, this was the stated role of the Ordo Malleus, which were the Inquisition's secretive Inner Order.
As per the Inquisitorial Remit, Inquisitors hold the absolute power to judge all who fall beneath their gaze. The Inquisition holds countless paths to death that usually correspond to the level of guilt of the condemned. The horrors of arco-flagellation, Penal Legion conscription, or binding to a Penitent Engine are a small sample of unique forms of penitence and absolution that Inquisitors use on a regular basis.
Inquisitors have the authority to condemn an entire world to Exterminatus if it is deemed to be irredeemably corrupt. Exterminatus, the obliteration of a world, is only resorted to when the level of corruption a world bears is so monumental that it cannot be wiped out by any other means.