"A more primitive being would describe it as a Demigod.It's as close a description as any. The Enemy needs access to our reality, and so they teach rigged versions of the Art that fool their would be servants here to open doors to places they shouldn't, and things get through. Things the Enemy has put there, waiting for the foolish. Spawn of their own, sent to recreate worlds in their image, so that they can enter from Outside. So they can leave their prison. This was one such thing. The Haxan and the locals thought they would have the power to send it back via the book, and could in that fashion control it. It is not the sort of being who takes well to having it's will suppressed. It would have ended in disaster."