Scholars, mystics, and mages alike all disagree on what exactly the Reideine might be. Some say it is a curse handed down upon the people of Kedrana from the Ancestors for some ancient crime. Others say it is a magical affliction, or a physical disease, hopping from host to host, spreading its plague across the world. A rare few speak in dark corners of it being a malign intelligence, plotting and working beneath your skin and behind your eyes for some unknowable, unstoppable goal.
What is known of the Reideine is this; whatever might spur it on, it seems to manifest randomly upon denizens of Kedrana. Pure, Impure, Fluxborn, it apparently reaps each with indifference. Once one has been touched by the Reideine, its mark soon manifests itself upon their body in some fashion. Due to the mystery of this mark, people bearing it are universally reviled, no matter what background they hail from. Perhaps it is nothing, perhaps it is benign, but who is willing to take that chance?
Those who are branded with the mark of the Reideine are Outcasts, doomed to live a life of solitude and fear. Even fewer are those who claim to follow the strange twists in fate and chance that follow any Outcast, these people are known as Reidenaya.
On the surface, it is impossible to distinguish an Outcast from a normal citizen of Kedrana without seeing their mark, although the odd way they tend to alter the world around them eventually becomes noticeable if they stay in one place for too long. Even if you find a mark upon someone, not a single soul has ever found a way to tell an Outcast from a Reidenaya, nor any method to remove the brand once it manifests.