WARNING: This article contains spoilers if you haven’t watched past the season 12 finale of Supernatural.
The Spawn of Lucifer
Jack is the best thing since sliced bread for Supernatural. Sure, he brought in a bunch of weird-even-for-Supernatural dimension hopping, but Jack himself brings light into the show it hasn’t seen since the beginning.
For a refresher, Jack is the Nephilim abomination spawned from Lucifer himself. However, Jack took after his human mother, Kelly Kline, a heart-warming person that gave her life so that Jack would be born. When Jack was born, he asked for his father, but he didn’t mean Lucifer. He meant Castiel, who took care of Kelly up until the moment she gave birth.
The Winchester boys were understandably concerned about the child of Lucifer coming into the world, but eventually, they saw that it was a blessing. Jack gave them everything they thought they’d never have: a son.
The Boy with Four Fathers
Jack’s blood father is Lucifer, but his chosen father is Castiel. However, it doesn’t just end there. Sam and Dean also stepped up the plate to fill that role. The Winchesters are more than just uncles to the Nephilim.
Castiel plays the role of the encouraging, supportive father. He’s the one wizened with age and experience, trying to tell Jack that everything will work out in the end. He can teach Jack about his angelic nature and also reassure him when he loses it. Cas knows the difficulty of being human and can properly prepare Jack for hardship.
Dean, on the other hand, takes on the role much like his own father, John Winchester. He delivers hard truths and hard lessons. He makes sure that Jack realizes that with great power comes great responsibility and that he has to be careful how he uses it. But still, at the end, when Jack was on his (first) deathbed, Dean was the one that was there for him. Despite being the one who doubted Jack the most, Dean seems to be the one that wants him to succeed the most.
Sam plays the role of a role model. Sam has had difficulties finding out who he is and rebelling against his destiny, much like Jack struggles. Much like Cas, Sam encourages Jack to be the best that he can be. However, Sam makes sure Jack knows that in the end, it’s his own choice to be good or evil and that choices have consequences.
Why This All Matters
Sam and Dean have always wanted families. They’ve even tried in the past to make that dream come true. But this far into the story, by season 12, they have long given up on that dream. They realize they’ll die bloody and alone as hunters with no family to carry on their name.
But Jack changes things. Despite being a fully grown young man, Jack is still just a baby when it comes to learning about the world. Now the Winchesters have the opportunity to teach a young boy the way they were taught. To carry on their legacy.
And the best part is is that Jack has been very receptive. He uses his powers for good, and when he loses them, he still wants to be a hunter and save the world from monsters. Even when he’s down, Jack wants to risk everything to save people. Just like his dads.
Maybe the Winchesters won’t ever have families of their own, but their legacy will still live on with Jack the Nephilim.