Cult of the Dragon
The Cult of the Dragon was founded by the Mandragora of House Xeduus. Although it appeared to be nothing more than a simple messianic cult which believed that the Dragons or their kin were to one day return and deliver the world from evil, the actual purpose was far more sinister. It was designed to subvert humans to the cause of the Mandragora.
Essentially, the Cult espoused the virtue of loyalty and the acquisition of personal power and wealth. Followers believed that their enlightened state would elevate them to the notice of the Dragons who dwelt "Beyond the Veil" i.e. human understanding. For the poor, it offered the chance of something tangible; for the rich, even more wealth and power. Magical illusion, charm, and compulsion spells did the rest. Mandragora shapeshifters formed the higher echelons of the Cult, sometimes replacing those Cult members who had perhaps risen too far. Such personality changes were attributed to their enlightenment, being closer to the Dragons - none suspected how true it was, that the replaced Cultist was now a Mandragora! With Mandragora in positions of power, they could easily sabotage any attempts at defence during the invasion.
Again House Xeduus failed to take the measure of human nature. Greed overcame good sense, and more human nobles were recruited. Previously, the recuitment of the poor and disenfranchised members had escaped official notice. When the city watch of Tagraad investigated at the request of the concerned parents of the nobility, they were more than a little disturbed. Especially when they found that the cult had significant number of followers and were heavily armed. The Cult took to the streets during the days of violence of the Food riots in Tagraad - and many lay the blame squarely at the feet of the Cult for sparking them in the first place.
When a number of the Cult leaders were slain and reverted to their natural form, the truth was quickly revealed - especially as there were vague rumours of the Mandragora abroad in the wilds of Volkrania. The Cult of the Dragon is now illegal in Volkrania. Despite this, it is still active - many of its members believing the the cult leaders were transformed in death to near-Dragons. Although illegal it can often be found underground, occasionally working with The Remnant. The cult is well-equipped (with a large number of magic users) and they are utterly dedicated to their "Draconic" masters and leaders.