A Transient is a demon that dwells within the shadows of worlds who's home world is co-existant with our own known as The Shadow Realm. It is large with a dark grey skin and jet black eyes. They can fly, and are known to work for a highger power in the Shadow Realm.
Oh my God what's happened to Jon!?!?
That thing isn't Jon. That thing is a Transient. A being of pure evil.