Well, I have a couple different theories on just what could happen, and I haven't really decided what I think is the most likely, because quite frankly Kripke throws things out there that we never really expect. But whatever happens, I think it'll end violently, suddenly, dramatically, and one of the boys is going to die. Which means the other one's going to die, too, I think... or fade out and no one really knows what happens. (I figure if I brace for the worst, then if/when it ends happily, I can be pleasantly surprised. :)