Although overall season 11 of "Supernatural" was significantly more dramatic and had their audience on the edge of their seats, the show writers made an amazing effort to shake things up in the season 12 finale as well. Since the show took a step down from God and the Darkness, it was difficult for fans to imagine something better than that coming up in the following season. Although these seasons are not at the same level, major events marked this year's finale.
Sam's approach towards Jack
With Crowley sacrificing himself for the well-being of the Winchesters and the whole universe, Mary trapping herself and Lucifer in the other dimension, and the Nephilim Jack was born; it is safe to say that the writers did everything they could to set up a rich plot line for the following season.
The stars of "Supernatural" Jared Padalecki and Jensen Ackles shared some details about season 13 in Comic Con. According to them, Sam Winchester will take a more compassionate approach towards Lucifer's child, whereas Dean will not be okay with this attitude.
What will happen with Castiel?
And the good news that everyone already knew about season 13 is that Castiel is not dead (well not completely at least). The next season will pick up a few seconds after the finale, Castiel will be back; however, he will not be the same. His death will affect him to his core, and the decisions he will continue to make will not be the same as the Castiel that we have grown to love. According to Misha Collins, it will take a long time for Castiel to be back, since this time he is "more dead than usual." We will slowly be getting Castiel back; however, not every part of him will be found in this new version.
The first appearance of Castiel will be in episode 6 of season 13. Another aspect of his death is how the boys will be dealing with it.
How are we getting him back?
The season will pick up immediately after all the events that went down in the finale, and one of the first scenes will be Dean kneeling over Castiel's dead body.
He will attempt to call God to bring Castiel back, but then both of them will start the process of grieving and trying to recover from the loss of their friend. The fans never really took Castiel's death seriously due to the writers' continuous use of such dramatic moves. However when he does come back, he can be considered as more of a lifeless body, and he will be found in another realm that has been talked about but never discussed before with only a powerful being as a companion (which is apparently played by a great actress).
Only a few days after season 12 ended, Jared Padalecki accidentally revealed that Misha Collins would be filming the Scooby Doo episode with them, thus showing that Castiel somehow will be back. This came as no surprise to the fandom, as they were already expecting for their favorite angel to make a comeback.
