Supernatural Story Finders

I am looking for a fic that I have the urge to read but cannot for the life of me find. I've gone through my bookmarks and saved lists, but I haven't found what I think I'm looking for.

It was a Castiel/Dean story where they had come up with an alternate way to stop the apocalypse. I know they get rest of the Angel Squad on board, because Dean spends various battles possessed by Michael (who has done an about face on previous stances and is now a friend of Dean and Castiel). Michael, however, does not possess Dean all the time, and the rest of the time he wears Dean's former aunt (she had been John's sister, and had been braindead in a hospital due to an accident, I think). They also get the Vatican on board to help stop the apocalypse, as Dean and various angels make several trips to Europe to meet with people snd collect things. I believe it was posted to Archive of our Own, but I'm not sure.

This sound familiar to anyone?

So, I've been reading books about the history of Christianity - not because of Supernatural, they're for something else - but one of the topics that keeps popping up is the history of the god that is now most widely recognized as the God the major monotheistic religions.

Long story short, Capital G-God originally existed as Yahweh and he was part of a polytheistic pantheon like basically all deities of his time were. His role in that pantheon was as the god of war, something similar to the role of Aries in the Greek pantheon (which part of the reason why the Old Testament of the Bible is full of such violence - it was pretty much considered acceptable for gods of war to behave in such a violent, jealous, petty, capricious manner because there were other gods in the pantheon to balance them out). Over time, as monotheism evolved, people went 'Hey, we can't pray to a god of war about love, or for good crops, or other stuff that NOT WAR', so Yahweh evolved from being a specialty sort of god (war only) to a more generalist type of god (one who was involved in everything and, thus, could answer all prayers).

Are there any fics that deal with this at all? The idea is stuck in my brain now and I want to read about, but I've searched the 'god' character tag on multiple sites and haven't found anything. I'm willing to be open minded, but here's possible stuff I would be really, really, interested in reading:

1) God not as a benevolent being, but as Yahweh, god of war still.
(Maybe he faked good behavior long enough for monotheism to get off the ground and then went back to his warmongering ways? It would fit with what we've seen of the rest of the gods on the show. It would also explain why he can't be found - everybody's looking for the wrong kind of being.)

2) The transition from Yahweh, god of war to Capital G, benevolent and merciful Almighty.

I'm mostly interested in #1, though because I think it fits better with the show. However, I'm open to anything. If there's a Yahweh fic out there (or one that calls him Allah or Jehovah, it doesn't matter to me) I would like to read it.

Thank you for your recs. :)