The Phyrus is an elaborate X in a circle. It is pronounced (FI-rus). They symbol (and those symbols related to the phyrus in their mythology -the pyramid, disk with a whole in the center, and chaos spiral) is often secretively present in many organizations and governments emblems.
This organization is one that keeps out of the public eye. It is old and secretive, though it acts for the good of the mortal world. The reason they remain secretive is that if the organization was known or its purposes revealed, people would interfere with their workings either out of greed or good intentions.
Their purpose? To ward the world from the Fey. They seal the gatepoints that would lead from the fey realms and the mortal world. They do so with drops of silver or silver phyruses, imbedded into rocks, building, and foundations. They can also use the phyrus to protect locations and important people by the presence of a Phyrus. To that end, they have hidden their symbols of fey warding in the important items of every major church and government.
The Fey ARE CHAOS. They are the extra-dimensional manifestation of chaos. While an occasional fairy and the like is an annoyrance, their presence is a requirement for magic to function. However, a fairy mound or full portal to their realm will begin to erode the very fabric of the world. So the Silver Phyrus work a balancing act between law and chaos, magic and mundane.
The Fey do not mean to destroy our world, but their mere existance can put it in jepordy. They need an occasional contact with a world of order, to maintain their own limited stability. While it is their nature to chaffe at the workings of the Phyrus, some of them understand their reasoning.
However, there are dark Fey who would like nothing more than to plunge the material world into chaos, so they can mine the order for their own purposes. These fey used to manipulate mortal/ material rulers to their own ends and to interfere with the Phyrus’s working. Thus the order began protecting those in power.
Those who understand the power behind magic, often work towards freeing Fey and bringing them to material realm. Some do it for their own purposes, others for the benefit to the world that easier magic would bring. The Phyrus monitor the places where the Fey can be brought across and where they have in the past (those places sealed by a Phyrus). The Silver Phyrus need to stop those being carefully, as to not reveal their existance.
Thus the world is kept safe by a few courtiers, silversmiths, woodsmen, and the occasional mage. All of them linked by the Phyrus and a need to keep the world safe.