[SPOILERS ahead for the Supernatural season 10 finale.]
It has been a while since we here at Screen Rant have had the opportunity to discuss Supernatural , but that has to change after the season 10 finale, 'Brother's Keeper', set up a potentially cataclysmic storyline for the show to follow in season 11. Yes, those of you who remember the disappointing Leviathans of season 7 may well view the upcoming Darkness unleashed at the end of last night's episode with a bit of well-earned trepidation, but the steps involved in getting the Winchesters to the point they were bum-rushed by a massive black cloud (one that even Death seemed weary of) generated a surprising amount of intrigue.
It also didn't hurt that, despite the road the Winchesters had been on all season, trying to cope with and then lose the Mark of Cain that Dean had acquired (so he could kill Abaddon), the season decided to take the road less traveled (with this show anyway) and not kill one or both of the siblings. To be honest, it certainly looked like that’s where things were headed after Dean went full Cain (but thankfully not full Dean Cain) on Castiel, before taking off to drink beer and wake up on the floor of one of those oddly familiar hotel rooms hunters of the supernatural seem to love.
Yes, considering the emphasis the season has placed on the seemingly immutable nature of the Mark of Cain (and now, the evil that lurks behind it), there was little recourse left for the violent-tempered, mark-sporting Dean Winchester but to be whisked off to the afterlife, sparing everyone left in the land of the living the brutal beating he would inevitably have gotten around to. Instead, 'Brother's Keeper' had a few surprises in store for viewers who've come to believe that it's not a Supernatural season ender unless Sam or Dean takes a temporary dirt nap.
For one, the episode managed to tell a fairly consistent, straightforward story. Utilizing the thread with Castiel, Crowley, and Rowena (Ruth Connell) to much the same effect it did the showdown between Sam and Dean, made 'Brother's Keeper' a far more engaging and unpredictable story than it otherwise could have been. And that's been a mark (no pun intended) of the season, despite the usual kinds of bumps your typical 23-episode season endures along the way. Supernatural managed to keep the Mark of Cain storyline fairly consistent, and the addition of Rowena (as both a potential antagonist and the only chance to free Dean from his curse) was a welcome one – especially during the climactic moments of the finale.
So let's talk about the Darkness (sadly not the glam rock band from Suffolk, England, though if Supernatural wanted to begin next season with 'I Believe in a Thing Called Love' that'd be just fine) coming to wreak havoc after Cas, Crowley, and Rowena managed a pretty spectacular spell. Specifically, one that unlocked the Mark of Cain and set Rowena up as a potential game-changer - with her witchy ways now being strong enough to stop Crowley in his tracks and turn Cas into a rage-filled hate tank with bleeding eyes.
As it turns out, Dean's taco-filled heart-to-heart with Death was about more than striking a bargain to end his life and take the curse along with him – well, it was for Death anyway. You see Death used the occasion to educate Dean on what the mark really was. It wasn't just a curse, or a way to imbue someone with the power to kill an incredibly powerful demon like Abaddon; it was a lock, binding an evil so great it was simply called the Darkness, an evil that existed before God created light. That's a pretty shocking revelation – one of Biblical proportions, you might say – that not only helps unleash the Big Bad for season 11, but also suggests this isn't the last we'll see or hear of the Mark of Cain.
See, the mark was important enough that even though Death has been after the Brothers Winchester for quite some time, he first suggested that Dean share the burden with someone else – spread out its nasty influence between two people, so that one person doesn't do what Dean did all season long (i.e., alienate people even more so than usual with a series of punches to the face). Obviously, Death was suggesting that Dean and Sam somehow become bearers of the Mark of Cain, keeping the Darkness at bay in perpetuity (which sounds like a storyline with some series-ending potential, if you ask me). Now, either Dean didn’t see that that's what Death was getting at, or he really didn't want Sam to have to bear the weight of the mark, so he opted for what was behind door number two: Dean gets whisked off to a far-off place in exchange for Sam's life.
Well, he pretended to opt for door number two, but as Dean Winchester is wont to do, he just went ahead and made up door number three: run Death through with his own scythe. So what does this mean for the future of Supernatural and a series that didn't like the concept of death so much it finally just killed the physical embodiment of it off? Well, it seems that death is still an option, since Rowena opted to kill Oskar, the boy she made immortal (because he was the only thing she ever loved), in order to gain her freedom. It certainly looked like Oskar died, but maybe the universe hadn't caught wind of Death's passing just yet. Maybe Death's absence will become a major issue when the new season kicks off, or maybe it'll just be a position someone in the cast will have to fill. It'd be kind of wild to see a world overrun by the Darkness and yet somehow devoid of death (making it a literal Hell on earth scenario?), but we'll have to wait until fall to find out.
At any rate, 'Brother's Keeper' didn't so much close out season 10, as it simply opened the door extra wide for season 11 to come barreling in…and that's okay. At this point, Supernatural isn't so much about conclusions as it is finding ways to keep the story going. Death and the Mark of Cain are gone but not forgotten, Dean and Sam are back together and possibly in a world of hurt, and Rowena is running around with a dangerous spell book and the power to use it. All in all, it was an unexpected ending that somehow turned into a promising beginning.
Supernatural season 11 will premiere in the fall of 2015 on The CW.