It is quite possible that you have interacted with one during your adventures and not even known.' ( NPC: Magistrate Marduke) A major part of a Cultist's job, depending on their placement inside the organization, is infiltration of places (as listed above) largely, this is accomplished with an Orb of Illusion, an item given to every Initiate: 'These artifacts are used to disguise a cult member, allowing them to gain safe passage, infiltrate, or simply blend in with an enemy.' ( Quest: Drag and Drop) The Cult only wears a uniform for ritual and ceremony.
Nearly every city, from the capitals to the small hamlets and hovels of both the Horde and Alliance, have Cult members hidden amongst their citizenry. 'The Cult of the Damned has grown large in scope. And they do things which the undead cannot, such as infiltration in Valiance Keep ( Quest: The Hunt is On) and in Sholazar Basin ( Quest: Exterminate the Intruders) They are an arm, a separate section, to the Scourge, and a vital one at that: they are the mortal servants of the Lich King. Comment by 593826 The Cult of the Damned, originally led by Kel'thuzad (a soul conscripted like so many of its other members, by the subtle beckoning of the Lich King enclosed inside the Frozen Throne), the catalyst of the destruction of Lordaeron, and those responsible for the death- and raising, through necromancy-of thousands, even millions, of men, women, and children.