I just caught up on Supernatural, and I have a question.
Lucifer said that there were five things (including himself) that couldn't be killed by the Colt. What do you think are the other four?
One theory already posted:
I got the distinct impression the other four things were the Horseman. Which makes sense especially if you go with the idea that Lucifer just assumed everyone knows it wouldn't work on God himself. Some things just don't need to be said.
My theory is that the five things are:
God
Lucifer
Michael
Gabriel
Raphael
Basically, I'm thinking that the five things are God plus the four archangels who have been introduced/mentioned. Lucifer is an archangel, so it would make sense that his archangel siblings would have similar levels of power (Michael, especially, as he was the one to defeat Lucifer the first time).
Castiel also said that there were only four angels who had talked directly with God, so this would fit in well with Lucifer's quote about the five things (again, assuming that one of the five is God).
I believe there are supposed to be more archangels in scripture, but Castiel has already said that our scriptures are very inaccurate. As an example, Uriel is supposed to be an archangel in many belief circles, but he was Castiel's subordinate in the context of the show (except for a brief period while the other angels were questioning Castiel's judgment). Also, Catholicism often only recognizes archangels Michael, Raphael, and Gabriel (plus Lucifer as a fallen archangel), so the writers have some precedent.
My theory is that the four siblings will all play a role in the series finale. [I'm also assuming that Zacharia is not an archangel. I don't believe it's been mentioned one way or the other, and the closest archangel (pronunciation-wise) is Zarachiel (as mentioned by St. Gregory).]
Sasha Roiz could guest star for the shirtless episode.