The Supernatural season 15 finale tied up most of the loose ends in the series, but there are still a few unanswered questions that may haunt audiences for years to come. The biggest question marks hover over new plot points introduced in the show's final episode and unresolved conflicts from earlier in the season. With no new episodes forthcoming, it's up to fans to speculate about what Sam's life was like on Earth or what Cas is up to in Heaven.
The final episode of Supernatural, season 15, episode 21, "Carry On," starts with Dean and Sam Winchester returning to the Men of Letters bunker after helping Jack defeat God. The penultimate episode, "Inherit the Earth," ended with Jack assuming the role of omnipotent ruler and restoring all the people Chuck destroyed. With (temporary) peace on Earth, Dean and Sam enjoy a brief period of retirement before tackling yet another hunt. After cuddling the most adorable dog in the world and visiting a pie festival, Dean drives with Sam to track down a nest of vampires.
The hunt goes well at first, but ends tragically when Dean is impaled on a piece of rebar. After a touching speech about how Sam can go on with out him, Dean dies in Sam's arms, going out in the line of duty. After Sam gives Dean a hunter's funeral, the story picks up in Heaven, where Dean is reunited with Bobby, who tells him that Jack pulled down all the walls in Heaven, letting souls mingle freely with their loved ones. Mary and John are living together just a few miles away and Cas is somewhere around too. Back on Earth, Sam has a son named Dean and is living with an unnamed woman. After a long and happy life, he too dies, only to see Dean again in Heaven.
Is Sam's Unnamed Wife Eileen?
One of the biggest unanswered questions after Supernatural's series finale is who exactly helped Sam start up his apple pie life. Sam is shown with his son Dean at various points over the years, but the only glimpse the audience gets of Sam's wife/girlfriend is a hazy, long-distance shot of her standing on the porch while Sam and his son play baseball. Eileen, Sam's love interest in season 15, was erased from existence in episode 18, "Despair." She was presumably revived by Jack in the penultimate episode, "Inherit the Earth," but it's never confirmed.
After the tearjerker scene in "Despair" in which Sam is powerless to save Eileen and had to keep fighting despite her loss, many fans wanted to see Sam find her again in the finale. After the all the heartbreak Sam endured, Eileen's revival in episode 6, "Golden Time," seemed to renew his hope. Sam's relationship with Eileen was refreshing and fun, and seemed to be a light at the end of the tunnel for the hunter. It's never outright stated that Eileen is the one with whom Sam finds his happily ever after — probably due to the filming restrictions brought on by the coronavirus pandemic — but the implication is there. It's all up to the fans.
What Becomes of Sam And His Family?
Supernatural's season 15 finale shows Sam living a long and happy life with his family and son Dean, but doesn't get too deep into the details. How does Sam get together with his beloved? Where do they settle down? Where's the dog? Sam's life post-Dean restarts with a hunt — do he and his son carry on the family business?
The plethora of family photos in Sam's house and the anti-demon possession tattoo on his son's forearm seem to suggest that Sam has been open about his hunting life. It's easy for the audience to imagine Sam sitting his son down as a teenager and telling him stories about his heroic Uncle Dean. Sam may have taken some time away from hunting to raise his child (he obviously has enough free time to buy a suburban house and play some baseball), but it looks like his son did later carry on the Winchester family tradition of killing monsters.
Do Cas and Dean See Each Other In Heaven?
In yet another COVID-related casting cut, Castiel doesn't appear on screen in the Supernatural series finale, much to the disappointment of fans. The angel was last seen in episode 18, "Despair," sacrificing himself for Dean after confessing his love to the stoic hunter. In the final episode, it's revealed that Castiel hasn't been consigned to the Empty for eternity — he apparently helped Jack rebuild Heaven. "So Jack did all that?" Deans asks Bobby, after he explains what Heaven is like now. "Cas helped," Bobby replies.
Castiel is never shown reuniting with the Winchesters, so one of the biggest unanswered questions in the series is how Dean might have reacted to seeing him again. How does Dean feel in the face of Castiel's love confession" was neatly sidestepped by the writers, implying that Castiel's love for Dean is unrequited. If/when Cas and Dean did see each other again in Heaven, it seems likely they'd resume their friendship, having a few beers together each week. Without any concrete answers, though, Destiel fans are welcome to paint a picture of Dean and Cas living happily together in their own Heavenly home.
What Is Jack Up To In Heaven?
The last Supernatural fans saw of Jack, he was waving goodbye to the Winchester brothers on his way to Heaven, at the end of episode 19, "Inherit the Earth." Since then, Jack apparently rebuilt Heaven, making it a better place for human souls. He may also have rescued Castiel from the Empty, although it's not clear. So what exactly is Jack up to in Heaven? He seems to be taking a hands-off approach to ruling the universe, but he has made some changes. The world is currently in perfect balance between light and darkness, so maybe Jack will take that time to implement some other slight reforms, making Heaven and Earth better places to live and love.
What Happens To Other Hunters?
Hunters from Winchester's world — such as Donna, Jody, Alex and Claire — as well as The bunker is empty now, so perhaps Sam handed the keys over to a deserving successor. And the audience can only hope that Charlie's been reunited with her girlfriend Stevie and they're eating eggs between kisses.