Hi! I'm looking for a fic that i read some time ago but i cant remember the title or the author. It's set in season six and basically Cas is making technically immoral decisions so he can win the war against Raphael, and it's corrupting his grace and (i think maybe) killing him. So he gives a part of his grace to Dean for safekeeping because as long as there is a part of his grace that remains pure he can use it to heal his own grace. I think that it mixes with deans soul and when he tries to get it out again he takes part of dean with it and they end up bound together? i'm a little hazy about that bit. And then there's a sequel from Sam's pov where they get his soul out of the cage and he sees how Dean and Castiel's relationship has changed. My thanks to anyone who can help me find this becuase i really want to re-read it :)
Edit: Found!