Officio Assassinorum

In the fictional Warhammer 40,000 universe, the Officio Assassinorum is an Imperial agency that trains and employs different assassin temples to further the goals of the Imperium of Man. Although the Inquisition strikes fear in the hearts of all Imperial citizens, loyal and corrupt alike, the deadly disciples of the Officio Assassinorum strike fear in the hearts of even the most savvy, battle-hardened of warriors.

Assassins are typically deployed alone wherever feasible, having been trained to operate extensively behind enemy lines with no support. Given the sheer political power of the organization and the fact that its operatives are known to have been used against rival High Lords, the authorization to assassinate a target must come from the highest echelons of Imperial command. For this reason, Assassins must always be fielded alongside an Inquisitor in the Warhammer 40,000 table-top game.

Temples
There are six major Assassinorum 'temples', each specialising in a different form or method of assassination;
 * Callidus Temple - drug induced shape-shifters who specialize in infiltration and disguise as their methods for affecting their targets.
 * Culexus Temple - those who are born with a one-in-a-billion genetic defect are ushered into the most mysterious of the four sects, that of psionic mind-assassins.
 * Eversor Temple - a combination of drugs, bio-engineering and psychotic fury are the tools of this shrine's trade.
 * Vindicare Temple - focusing on marksmanship and patience, this shrine eliminates threats to the Imperium with a single unerring shot

There are two more major temples that do not have miniatures in the game, and thus not much information about them has been compiled into official sources. One of them, Venenum, deals in assassination through poisoning. Of the other, Vanus, nothing is known (although the Latin word "Vanus" means "Empty", so the name could be a joke inserted by the writers).

The Officio Assassinorum also maintains patronage over numerous minor assassin temples and death cults.