User blog comment:Rafe Adler/"Who We Are" and "All Along the Watchtower" Discussion/@comment-1031724-20170520193751/@comment-1031724-20170525220046

Well... I was wondering if Jack's power went into Mary when he was born (seeing as how she was right there and knocked out by the light before waking up to punch the devil in the face), and she doesn't know it until defending herself from Lucifer's wrath in the other world, leading Lucifer to either return with her, or suffer an unceremonious offscreen death just like Rowena.

Unlikely I know, especially since his very footsteps burned the ground, plus the rift was easily just a way to remove both Mary and Lucifer forever, but it was the "Crowley is God" theory that made me more confident to say this

Either way, Castiel will likely be revived, again, since it's said that Misha is in Season 13 (though not Mark Sheppard, so Crowley is gone for good)