The Adeptus Arbites are the hard fist of Imperial law, an arm of the Adeptus Terra charged with enforcing the Lex Imperialis upon every world that bows to the Golden Throne. They are not concerned with the petty crime that occupies local enforcers, the theft, the murder, the unpaid tithe, for such matters are beneath them. The Arbites exist to guard the greater order: to crush the corruption that threatens the Emperor's rule, to see the Imperial Tithe delivered, and to stamp out the first sparks of heresy, witchery, and xenos taint before they can catch and spread.
Upon an Imperial world the Arbites answer to no local governor or magistrate. They are the last and most absolute authority, bound only to their own commanders and to the Judges of the systems and sectors above them, and they have been granted the right to serve as judge, jury, and executioner over any citizen who breaks the Emperor's law. The whole vast institution is overseen from the Hall of Judgement upon Terra by the Grand Provost Marshal, who holds a seat among the High Lords, with the Marshals of the Court commanding star-spanning precincts beneath him.
Internally the Arbites divide into two callings. The Judges devote themselves to the law itself, to the ten millennia of accumulated case law and precedent by which the Imperium is ruled. The Arbitrators are the militant arm, the armoured enforcers who go out to apprehend and to punish. Sheathed in black carapace and enclosing, rebreather-fitted helms, wielding combat shotguns, power mauls, and suppression shields, they descend from their fortress-precincts upon lawbreakers as living proof that the Emperor's justice, however long delayed, is never in the end escaped.
Imperial Agents
Order of battle
The Adeptus Arbites field the units of the Imperial Agents — a detachment from the roster:
Kindred formations
Other Imperial Agents formations
Imperial NavyThe vast star-fleets of the Navis Imperialis, kilometres-long warships that rule the void, escort the Emperor's armies and bind the Imperium's worlds together.
Officio AssassinorumThe Officio Assassinorum is the Imperium's institution of sanctioned murder, maintaining secret Temples where killers are forged into living weapons. Each Temple perfects a distinct lethal art: the impossible sniper shot, the perfect infiltration, the berserk slaughter, the anti-psychic horror. When the highest powers of the Imperium require a target erased, they turn to these silent executioners, whose marks almost never survive.
Rogue TradersPrivateer-explorers bearing the ancient Warrant of Trade, licensed to trade, conquer and treat with aliens beyond the Imperium's edge in the Emperor's name.
Sisters of SilenceThe Sisters of Silence are an ancient order of soulless women, warriors whose very presence is poison to psykers and daemons alike. Born as Untouchables, they render their oaths without a single word, wielding flame and blade alongside an aura of null that smothers sorcery. They serve as jailers and executioners of the Imperium's most dangerous witches, and their arrival heralds the hunt for a psyker of terrible power.
The InquisitionThe Inquisition is the Imperium's ultimate authority, a shadowed order that answers to none save the Golden Throne. Its Inquisitors hunt heresy, daemon, and alien alike, wielding the power to command fleets, judge worlds, and condemn the corrupt to fire. Divided among great Ordos, each dedicated to a different existential threat, its members walk a razor's edge between salvation and damnation in defence of Mankind.