"...Yeah, sure. Okay, so: magic is real! Surprise. There exist three kinds of 'daeva': demons and angels and fairies. Drawing the right circle summons us. Normally there would be more bindings on the circle than there are on this one to prevent me from rampaging but I don't feel like rampaging so it's okay. The standard deal is that you summon one to do some magic for you. Demons make things, angels change things, fairies move things. You have to work out something the daeva wants - fairies are easy to pay because they can't just make whatever they want at home like that." He snaps his fingers. "I don't know who was summoning an unbound demon if it wasn't you who drew the rest of this circle - actually, come to think of it, they should probably be found and scared out of doing that, unbound daeva are dangerous."