WARNING: The following contains spoilers for Season 15, Episode 11 of Supernatural, "The Gamblers."
To the surprise of absolutely no one who has been watching Supernatural, Episode 11 heralds the return of Jack Kline. No, not a demon hiding in a Jack skin suit, but the real Jack -- the Nephilim son of Lucifer who was killed by God/Chuck, at the end of Season 14. He claimed he was doing the Winchesters a favor, as they -- along with Castiel -- had grown concerned that Jack's lack of a soul had made him far too dangerous for them to control. However, as this recent episode reveals, Chuck is actually just as terrified of his grandson's destructive potential as his adoptive family was.
Even in the immediate aftermath of Jack's demise, it was clear that the show wasn't done with him yet. We saw the confused young man wake up in The Empty, the dimension where the souls of dead angels and demons go, to find himself being watched over by Billie (Death) and The Empty's guardian, The Shadow. Jack has been there ever since, with our only clue as to his new purpose coming at the end of Season 15's midseason premiere, and Billie's announcement that, "It's time."
Time for... what? Well, now we finally know. Predictably -- though not unwelcomingly so -- Billie plans to use a resurrected Jack as a weapon against God.
Our reintroduction to the once-fallen Nephilim is a shocking one. After receiving a call from one of Sam and Dean's police contacts, Sheriff Evans, Castiel is aghast to discover that the Sheriff is calling about Jack -- who he has an old file on -- who has been identified at a crime scene. The CCTV footage shows Jack attacking a doctor. It cuts out for a minute or two, and when the tape resumes, Jack can be seen sitting at the slain man's desk and munching on his heart as if it was a light bite for lunch.
The plot thickens when Castiel finds a sword belonging to a Grigori at the scene. First introduced in Season 10, the Grigori are the Black Ops of angels, or, as they put it themselves, "a brotherhood of perfectly crafted beings." But, like most of Supernatural's heavenly creatures, this elite group of warriors is hardly heroic. As Jack points out when his next target manages to catch and kidnap him, the one he'd previously killed was presenting himself as a doctor in order to feed off of the human souls he was supposed to heal. As for his captor, who tortures Jack to try and find out why he's been murdering his kin, he prefers the souls of children.
While this doesn't exonerate Jack for his sins, it doesn't paint his victims in a sympathetic light, either. Castiel, meanwhile, has been hot on Jack's bloody trial, and bursts in to put down the Grigori and rescue his surrogate son. We don't get any context for Jack's killing spree until he's back in the Bunker, though. There, Sam and Dean welcome him back into the fold without question -- his previous digressions seemingly a thing of his past life.
Jack apologizes for not coming home sooner, explaining that he was worried his grandfather would sense him should he use his powers and kill him again. Billie also had to wait to resurrect him until Chuck was off-world. His heart-eating, as horrific as it was, is the first step in her plot to turn him into a God-killing weapon. We know that even God's soul is capable of being reaped, but Billie is likely forbidden, like all reapers, for directly bringing about death itself, hence why she needs someone to do it for her.
We've been led to believe that reality would collapse without Chuck, its creator, alive in it. But, Supernatural is full of contradictions and loopholes to its own lore. It could also be that Billie has designs on installing a replacement, or even that she thinks it's time for Chuck's multiverse to come to an end so life can begin again. Whatever her endgame is, it's nice, for now, to just see the Winchester family back together again.
Returning Monday, March 16 at 8 p.m. ET/PT on The CW, the final season of Supernatural stars Jensen Ackles, Jared Padalecki, Misha Collins and Alexander Calvert.