IMPERIAL INQUISITION
The Inquisition, formally called 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 Drukhari.
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.
In the modern 41st Millennium, the Inquisition is the most powerful organisation of the Imperium's many branches. Its agents, the Inquisitors, command fear and respect in equal measure. They are creatures of myth as much of flesh and blood, relentless beings who descend from on high to pass judgement upon the mutant, the traitor and the heretic. It is a rare citizen who does not dread drawing an Inquisitor's steely gaze, who does not experience the starkest terror in his or her presence. Every Imperial citizen, from the poorest of underhive scum to the highest and wealthiest of nobles, has heard the tales of death and destruction, of the all-seeing eye that condemns or absolves with impunity. Those who have crossed an Inquisitor's path and survived to tell of it are seldom eager to invite his attention again. Inquisitors are as varied in appearance and manner as the myriad threats they face. They range in age from fiery young zealots to hoary old veterans who have fought in the darkness for centuries. Some wear ostentatious robes and symbols of their allegiance, whilst others shun the trappings of status. Inquisitors commonly carry a wide range of weapons and wargear, so as to be prepared for any threat they might face. Some Inquisitors use outlandish weaponry, taken from defeated foes: exotic hardware, alien guns and Daemon-possessed weapons.
Inquisitors themselves care little for morality, and nothing at all for the Imperium's many laws and procedures, except when they choose to make use of them. They are the Emperor's left hand as the Adeptus Terra is his right, and stand in judgement over all the Imperium's organisations. Indeed, an Inquisitor is apart from the rest of Mankind in every way that matters. By ancient tradition, his authority comes directly from the Emperor himself; there is no hierarchy to which he must answer, and he is beholden only to his fellows. More than this, a bearer of the Inquisitorial Seal can requisition any servant in the Imperium to assist in his mission, from the lowliest of clerks to entire Space Marine Chapters and Imperial Navy battlefleets.
The Imperium is divided into five fleet zones known as the Segmentae Majoris. Every starship of the Imperial Navy is assigned to one of these Segmentae, and falls under the command of the respective Lord High Admiral who commands all the Imperial Navy assets of that Segmentum. The naval assets of an entire Segmentum are named after that division of the Imperium; i.e. all of the Imperial fleet assets in the Segmentum Solar are known as the Battlefleet Solar, all the assets in the Ultima Segmentum are the Battlefleet Ultima, and so on.