So where do you think Show is going with Mary?
I can't help but think she is going to tie into the Nephelim storyline. I keep coming back to the whole "mother" and "sacrifice" thing they've got going this season. My guess as stupid as it may sound is that in order to "defeat" the Nephelim, Mary sacrifices her relationship with her boys and becomes the "pseudo parent/caretaker" of this extremely powerful being and returns to Heaven or goes off with it permanently. Mary isn't happy here, she feels she doesn't belong. She won't let them kill him as he's just a child. She now has a purpose and this child to raise as its real mother will have died and Lucifer returned to his cage once more. Maybe they will even have Mary initially bond with it thereby truly twisting that knife a little deeper into Sam and Dean. ;). This will of course devastate Sam and Dean but they will understand why she wants to do it as well as the devastation to the world if she doesnt.
I still can't figure out how they plan on letting him (it?) live. They think they have problems powering down Cas all the time in their writings? I got the Demon/Human anti Christ choosing good and making himself scarce but if they try and pull that a second time then I'm going to cry foul. The other thing I can't shake was the reference to the "soul swap" that the warlock was planning to do to Sam to bring his brother back. Have there been other such references this season? I'm just wondering if that will somehow also come into play at the end?