Obsidian Mirror Oneiroscopy (magic school)
First come the nightmares, night after night where the Magi dreams only of timelessly staring into an ink-black mirror. Then comes the voice, coming to the would-be practitioner from a nearly-invisible presence lurking just behind their shoulder, whispering truths into their left ear which fade with the rising dawn. Those Magi with the volition to listen (or those too weak-willed to shut the dreams out) soon find occult revelations spring to their mind, the culminations of the tutelage provided by the Presence in the Mirror. Originating in Sarradon, it is thought to be spread through 'infected' texts to particularly susceptible Magi. Having wormed its way across Aeras like a cancer visitations have now occurred as far afield as the Continent.
To those Magi who do listen, the Presence provides teachings in the Arcana of Dark, Air, and Dream. In the long term Magi often suffer from declining sanity, and many of the maddest have disappeared into the Sarradonian Desert following whispered promises of unimaginable power held in a sealed vault somewhere beneath the trackless sands.