Supernatural is bringing back the half brother of Sam and Dean Winchesters.
The last time we saw a glimpse of 'Adam' was in season 11 episode 'The Devil in the Details'. Sam is shown the memory of getting dragged in hell while Adam is seen in the background, still Michael’s vessel. This was just a memory but the last time we saw Adam in the flesh was in the season five finale of Supernatural, since then we’ve got cursory remarks about the lost Winchester brother, but he was never seen again.
We know the final season of Supernatural is coming this fall, and the series is bringing back most of the past characters of the show, one final time. Now, we’ve got confirmation one of the cast member returning to the show is 'Adam Milligan', the half-brother of Sam and Dean Winchester.
The first time we got to know about the existence of Adam was in season four of Supernatural where John’s phone rings but John Winchester was dead by the time, and Sam and Dean receive the call, and they go to kill the ghoul which was impersonating Adam. The ghouls were the children of the one John killed the year Adam was born, and they were there to get revenge on John by killing his family.
Sam and Dean kill the ghoul and give Adam the hunter’s burial he deserved, and it was thought to be the end of the whole affair. But like most things in Supernatural, the dead never stay dead, Adam is seen in Heaven enjoying his own paradise and the life he never got to live, but Heaven gives Adam a choice to get his mother back if he agrees to be the vessel of Michael and fight Lucifer when the apocalypse arrives.
Watch: Supernatural season 5 finale where Sam and Lucifer jump into the hole with Michael and Adam
The whole thing was prophesized, when the apocalypse comes, Sam will be the vessel of Lucifer and Dean will be taken over by Michael, since Dean is not willing to be Michael’s vessel, Heaven decides they need another method to get to Dean. They resurrect Adam in a ruse to position Dean into accepting Michael’s offer but when he still refuses Adam is taken over by Michael, and in the final moments of the finale of season five Sam is able to take control of his body, and he drags Adam and Michael along with Lucifer and himself to hell.
Castiel was later able to bring back the body of Sam in season six, but his soul, along with Adam, was still stuck in hell. Dean tries to bargain with Death for the soul of both Sam and Adam, but he is only given a single choice, and he chooses Sam which further compounds the guilt the brother felt about the loss of Adam.
Watch: Dean gets Death to give back Sam's soul
One of the best callbacks we got of Adam in the show was in the 200th episode of the show in season ten. The ‘Fan Fiction’ episode shows Sam and Dean visit a school where the students are doing a play on Supernatural. During the final performance, Sam doesn’t recognize one of the performers on stage, and the director tells him, it is Adam which makes the moment sour for all the viewers.
Adam is still in hell, and now finally the lost Winchester brother will be coming back to the show. Talking about the final season of Supernatural, co-showrunner Andrew Dabb said, “They’re realizing, ‘Well, we’re the Winchesters, but were we really doing this Chuck’s way?' Part of reclaiming that agency is a big part of the season for them.”