EDIT: I attempt to make the wings realistic. I've upload the original in my fanart folder if you preferred it. ^^ (I kinda do, in a way...)
Technically, this thing was inspired by cloudyjenn's fanfiction: "The Soul Piece". It was kinda what I was imagining during chapter 34 and it wouldn't go away until I drew it.
So, it's Castiel, in his true form, finally finding Dean in Hell after battling demons and taking on some collateral damage.