This is my first post to this community, and I admit (hangs head with shame) that I haven't read all of the recent posts that may relate to the current season plot arc, so I apologize if I'm repeating thoughts someone else already posted. I just wanted to throw out an idea, to see if anyone considers it a possibility.
What if the Mark of Cain (its mere presence on Dean's arm) is magically affecting the relationship between the brothers, causing discord between them?
Of course, they've always had conflict between them, but Sam's reasons for resentment seem to make less sense than usual. (He was in a coma, and Dean essentially chose not to pull the plug, which is a choice that many families have to make. But Sam wanted to die! He was ready to die! Well, if he still wants to die, they've got plenty of guns around, don't they? What's the problem?)
It struck me as odd that, after Dean got the Mark, the writers immediately abandoned that subplot to focus on the deteriorating brotherly relationship. I don't recall hearing of--or seeing--the Mark ever since it was introduced. But what if the subplot concerning the Winchester brothers and the growing resentment between them is actually a continuation of the plot about the Mark? (Or am I giving the writers too much credit for continuity?)
Is it giving off negative vibes that magnify Sam's resentment? Or is it picking up, and magnifying, Dean's resentment--and pain--at Sam's resentment? And, if so, either way, what the hell can we do about it? (Can Castiel remove a tattoo? IS it a tattoo?)
I know that the brothers have squabbled and sulked and brooded for nine seasons without needing any magical reason to do so. But it does seem, now and then, that they're gaining a little maturity, or appreciation of each other. I would have expected (hoped) for better behavior from both of them, after all they've been through. Could the Mark of Cain be creating obstacles to their relationship?
And if not, what the heck did the writers stick it in for???