@chukklehed The crystalline is contagious through saliva, blood, and inhaling the ashes of dead infected creatures. When the creatures die they turn into dust, which then gets ingested or into the water supply, which is how entire cities are being decimated elsewhere.
Those who are affected by the crystalline can "walk between worlds" -- see ghosts and visions of other realities, incorporeal demons, even read people's intentions -- until they die of the affliction. Spook's mask multiplies these abilities.
Magic is powered by dreams. The clearer you can visualize something working, the stronger the effect will be. Mages who push too hard or use magic too long will be deprived of their dreams. For some people this means insomnia -- for others, narcolepsy. Most power-users will slowly go mad either way.