Over fifteen seasons, with over three hundred episodes, Supernatural amassed a colossal, passionate fanbase that was constantly impressed and heartbroken by the show, with the latter coming in abundance through the series finale. Not only was it emotional to say goodbye, but the episode was hugely divisive, largely unpopular, and left a lot of questions.
Some of this can be chalked up to the circumstances in the world, such as why other characters did not appear, and some things, such as why Dean died in a relatively weak manner, are unanswerable since that's simply where the writers took the story. However, some narrative and character questions could have been answered, but, as of yet, they haven't been.
Did Donatello Get His Soul Back?
While he was arguably the best and most popular of them, Kevin Tran was not the only important prophet in Supernatural, with Donatello Redfield having his time to shine on the show.
Things did not work out perfectly for Donatello, even though he did survive the events of Supernatural. Amara consumed the prophet's soul, forcing him to learn to live like season six Sam, albeit without the remorseless killing and betraying of those close to him. With Amara now residing within Jack, one has to wonder if he could return his soul or even manufacture a new one despite the task's difficulty.
Does Sam Still Keep In Contact With Other Characters?
At the end of Supernatural, fans get snippets of Sam's life post-Dean, and, while he does some hunting, he had largely left it, being involved nowhere near as much as he was when Dean was alive.
Over the years, though, through hunting, Sam made a lot of friends. Family, in fact, who survived the events of the show in some capacity. Jody and the wayward sisters, Rowena down in hell, Jack and Cas out there wherever, and others, it makes you wonder how many contacts he had with them or if he saw them much after the show.
Did Sam & Dean II Do A Lot Of Hunting?
Sticking with the subject of Sam and his career in hunting post-Dean, it seems as though he at least taught his son, Dean II, about the ways of life, judging by his anti-possession tattoo.
That raises the questions of not only how much hunting did the two together and how much did Sam teach him, but also it begs the question did Dean II get up to much hunting after his father died. Did he get the Impala and continue the legacy or lead an apple pie life.
What's Going On With Adam?
The third and forgotten brother, Adam Milligan, son of John Winchester, was wildly mistreated in the show, pretty much left to rot in the cage with Michael and Lucifer with zero attempts to help from anyone.
When he finally did get out with Michael, God destroys Michael, taking Adam's body with him. Of course, Jack undid all of God's killings on Earth, so it is to be assumed Adam is now free from Michael and human again. What will he do with himself? Will he ever look up Sam, or does he do the right thing and get as far away from the Winchester name as he possibly can.
How Did Dean React To Seeing Cas Again?
While it was definitely an overall painful disappointment for everyone that Castiel does not appear in the finale, there is a lovely bittersweet moment when Dean reacts to Bobby telling him of Cas's role in crafting the new heaven.
After his confession of love at the end of season fifteen, the inevitable reunion of Cas and Dean has been on many fan's minds, and it is definitely a curious situation. How will Dean react? How will the two interact in the new heaven? They are an incredible pair, and seeing them happy together with Sam and the rest of the SPN family is something fans long for.
Did Jack Bring Back Any Other Angels?
Speaking of Cas being back, Jack's bringing him back from the Empty was a great inclusion of the finale even if we never got to see them—however, it does raise some questions.
Since Jack brought back Cas, did he bring back any other angels? Sure, they were the worst, with even the good ones going through their unlikable periods, but did he think to bring any back like the likes of Gadreel or Hannah to help usher in the new era of heaven?
Did Cas Keep His Deal With Ruby?
Speaking of the Empty, demons are also inhabitants of the space alongside angels, including Ruby, whom Cas basically killed himself to meet to find out about the Occultum's location.
While talking to Ruby, he promised that he would try his best to get her out of the Empty, and, with Jack able to do so, one has to wonder if Castiel kept his promise and got Jack to bring her back.
Did Jack Bring Back The Alternate Worlds?
Speaking of Jack and bringing things back, it is established that when he took over God's power, he reversed all the damage he did on Earth, but what about off Earth?
He took the time to craft new heaven after fixing Earth. Did he do the same for the other worlds created by Chuck that he destroyed like a petulant child? The sheer devastation Chuck caused cannot be understated; he destroyed worlds, many of them. With Jack now in power, fans have to wonder whether he brought them back along with their inhabitants or even if he created new worlds.
Where Are Jack & Cas?
In reality, perhaps the most significant reason the finale was lacking in characters was the worldwide circumstances preventing it from happening, but that does not help the disappointment fans felt at the lack of certain characters.
For Castiel to be confirmed to be back but not there to greet Dean in heaven, it just did not feel right. It is easy to understand why Jack was initially staying away, but the fact he is with Cas makes that too feel weird that he was not there to greet the boys. If they are not on Earth and not seeing the boys, then where are they? It's not like Castiel is God; he could quite easily live amongst Dean and Sam, or at least regularly see him.
Was That Eileen?
One of the most infuriating details of the series finale is not necessarily that Sam is off living an apple pie life—something many see as being against his arc—but the fact the show makes clear he has a wife but blurs her.
The assumption amongst most fans is that Sam's mystery wife was Eileen, but that is not a certainty. It would have been easy to somehow make clear that either his wife is Eileen or that it is just a random woman he meets in his life after Dean, and it is something fans are eager to know.