I think I've found a plot-hole in the books, remember how there was a Mite that had its legs removed and was put on the top of a staff? It's mentioned in the book that it's a wild Demon, not a summoned one. but then, wouldn't that mean it would dissapear back into the Ether?
I'm pretty confident that this is a Plot-hole, but if I've missed something, feel free to tell me :)