Is Sam Winchester Supernatural's final villain? As soon as Supernatural confirmed that it would draw Sam and Dean's story to a close with season 15, fans began speculating as to who the final villain of the series could be. After the events of the season 14 finale, this ultimate enemy appeared to be God, who had been orchestrating the brothers' lives from the very start, but had now grown bored and decided to end the world. Rob Benedict's deity remains a dark presence in Supernatural season 15, but could something more sinister possibly be brewing closer to home?
In the season 15 premiere episode, Castiel touched the gunshot wound Sam received after shooting God with his own weapon and had a vision of a seemingly evil version of Sam. No further explanation was offered, and it remained unclear whether this was an entity residing inside of Sam, a potential future, a flashback to Sam's days as a shell for Lucifer or something entirely new. The story was left alone for the past few episodes while the Winchesters handled the oncoming apocalypse, but now the possibility of an evil Sam Winchester has come to the fore more strongly than ever before.
"Atomic Monsters" begins with a highly realistic dream sequence taking place in Sam's head. The scene shows Dean hunting an unknown villain in a locked-down Bunker, passing fallen comrades as he goes. Eventually, Dean comes across his target, and it's none other than Sam Winchester with blackened, demonic eyes. Dean blames Sam's demon blood (a reference to Supernatural's earlier seasons) for his change in personality and accuses him of committing horrific acts of violence. Before he can strike his brother down, however, Sam uses his psychic powers to effortlessly snap Dean's neck, before waking up relieved in a cold sweat.
Now that this evil version of Sam has been glimpsed by both Castiel and the younger Winchester brother himself, it's perhaps safe to assume that there's some validity in these visions. Additionally, this week's episode of Supernatural planted the seeds for Sam to have a grudge against humanity as a whole. While conducting a relatively routine vampire case with Dean, Sam begins to express disdain for the people the two brothers save, and the fact that they get to live in blissful ignorance while the Winchesters constantly bail them out of paranormal pickles. Speaking to his brother, Sam complains, "we keep them from dealing with the truth, with what's out there, and we carry the weight." During Sam and Dean's traditional end-of-episode Impala debrief, Sam reiterates this jaded stance.
Some kind of evil Sam Winchester is beginning to look like a genuine possibility for the end of Supernatural season 15, but it's possible that the transformation won't necessarily be his fault. The B-plot of "Atomic Monsters" saw God reconnect with his ex-girlfriend, Becky. Despite an awkward reunion, Becky encourages God to do some more "Supernatural" writing to get out of his current mood slump. What the Lord eventually concocts in his new tale is such a dark and unsettling story that Becky is disgusted at what she's read and what God plans to do to the characters of Sam and Dean.
Consequently, Sam's turn to the dark side could still be part of God's larger plan. It has previously been confirmed that God controls the Winchesters' lives, and forcing one brother to kill the other would not only suit Chuck's need for literary drama, but would also explain why Becky was so unsettled. If this proves to be the case, Sam could turn bad, but God may still be Supernatural's final villain.
Supernatural season 15 continues with "Proverbs 17:3" November 14th on The CW.