Like so many before it, last seasons ‘Supernatural’ ended with a bang. After doing everything in his power to withstand Raphael’s might in the war for Heaven, Castiel finally gains possession of the ultimate weapon; all the souls in purgatory. With his newfound power, he smites Raphael and, at the start of this season, goes about spreading his word as the new God across the globe. But the power is not without its price; the Leviathan—created before angels and inhabitants of the primordial abyss (and the reason for Purgatory’s creation)—break free and escape into the world, destroying Castiel in the process. Able to possess any unfortunate soul that comes across the black ichor that is their essence, the Leviathan are the most intelligent and, quite possible, the most dangerous adversaries the Winchesters have ever come across.

With such a dangerous enemy on their heels, the Winchesters have remained on the defensive for the majority of the season. Though they’ve run across every creature this side of mythology and back again, none have infiltrated society and embraced technology to the level of this most recent enemy. But they are battling more than the Leviathan. Sam and Dean are dealing with their own internal struggles of guilt, trauma and the fear of facing the one thing that can never be changed—the past.

Dean watches as his best friend is falling to pieces before his eyes.

If there ever was a poster boy for suffering and self-flagellation, it’s Dean. Other than the year long hiatus during Sam’s absence between seasons five and six, Dean has been hunting for the better part of twenty years. Like a soldier who’s danced with death over and over again, it’s only a matter of time before a crack surfaces in the armor. Add to the normal stresses of a hunter the 40 year stint in hell, is it really a surprise that the cavalier, happy go lucky character we first met in the series premiere seven years ago is rarely seen? He’s lost too many people—Sam (twice), Jo, Ellen, his father, and now Cas. This list doesn’t include other colleagues he’s lost or the people he’s failed to save. The human spirit is strong but how much loss can one endure?

Dean has carried so much responsibility for so long, he often blames himself for things he has no control over. Since Death re-souled Sam, Dean has lived with the knowledge of the sparse wall maintaining his brother’s sanity. This mounting guilt is exacerbated when he watches Castiel succumb to the lure of power before he’s destroyed by the Leviathan. Castiel was Dean’s best friend, the bond they formed starting early during season four and Cas’s initial appearance. Cas’s turn towards his darker side was a choice made by the angel but Dean still feels the failure of not being able to walk Cas back from the edge before it was too late. It is through these perceived failures that Dean takes it upon himself to make the difficult decisions. This thought causes him to kill Amy in “The Girl Next Door”. While Sam sees Amy as changed, Dean doesn’t absolve Amy from her past or what she is. “But people,” he tells Amy before shoving the knife in her gut, “they are who they are. No matter how hard you try, you are what you are.” He may be talking to her but there’s quite the self-reflection in that line as well. Dean tried once not being a hunter and failed at the normal gig. Furthermore, it’s a testament to the aforementioned self-loathing he feels for the thing he has become.

The guilt Dean carries is a weight he doesn't know how to let go of

“Killing Amy wasn’t wrong,” he tells Sam in “The Mentalists.” “You couldn’t do it, so I did. That’s what family does, the dirty work.” And therein lies the crux of Dean’s issues. Fueled by Cas’s betrayal, his own failures, and losing so many people, Dean has slowly transformed into an overly cynical being. Couple that with his less than stellar opinion of himself—“I am 90 percent crap,” he tells Jo’s ghost in “Defending Your Life,” “I get rid of that, what then?”—screams of someone spiraling into the abyss of depression. Just how much further can he fall?

Though more attuned to other aspects of his character, Sam doesn’t have the issues with guilt Dean displays. In ‘Defending Your Life’, Dean asks him why Osiris didn’t put Sam on trial. Sam’s answer is a simple one: having a soul beaten and battered in hell, he’s finally at peace with himself. As he says, “the past is the past” and he can move on with his life. It’s an ideal that Dean has a ways to go before getting to but one is slowly moving towards.

Dean talking Sam off the ledge and back to reality

Now, for his part, Sam’s problem runs parallel to the Winchesters relationship throughout much of this season, fractured and disjointed. Though he’s far from the psychotic break from earlier in the season, Sam still has the less than joyous experiences of Hell running loose inside of him. While his struggles may not be part of every episode, there are subtle references, most often Sam reminding himself of what is real by embracing the pain from an old injury. The split condition of Sam’s mind and him hiding it from Dean strained their relationship early on and had Dean questioning Sam’s reliability—which may be understandable, is quite hypocritical when you take into account Dean thinking he always knows best [see Amy]. The mistrust between the two doesn’t last as long as one would think; they are both hurt from each others’ actions but the threat of the Leviathan, as well as their love for one another and the fact that, other than Bobby, they are all each other has.

This will be the last time with see these three together...

Speaking of the current patriarch of the ‘Supernatural’ universe, Bobby Singer has his own past to deal with, one that doesn’t make itself known until ‘Death’s Door’ where confronting it becomes the only way for him to relate the Leviathan’s plans to his boys. Bobby has always been a mystery, the stodgy uncle who’s crass and rude but brutally honest. He’s been with Sam and Dean since they were boys and has never disappointed. Like all characters, Bobby has his scars. Whereas Dean uses sarcasm and Sam brushes it off, Bobby’s gruffness is his one defense. We finally do see the depth of his scars, killing his abusive father as a young boy; an experience that has permanently damaged the veteran hunter. It’s not until death is knocking that Bobby has the courage to face what he’d been running from all these years.

One of the great things about ‘Supernatural’ is that, despite standing up to the things that go bump in the night, our heroes aren’t perfect. Their flaws are plenty and the mistakes they make have consequences. It’s what makes them human and being human, we need to remember that, no matter the good or bad we do, we always have the chance to redeem ourselves. We can make mistakes, be crushed by others actions or our own but when all is said and done, the past is just that and only effects your present and future as much as you allow. With Bobby presumably gone, the brothers are truly alone for the first time in their lives. How much they learn about redemption and facing their past will be a foundation for where Sam and Dean find themselves in the second half of this season.