Sam and Dean Winchester will be thrown straight into the deep end of parenting in Supernatural season 13, as they raise the child of the actual, real-life devil Lucifer himself. Last time fans saw the Winchester brothers in action, the threat of Lucifer was (temporarily) dealt with, largely thanks to the assistance of Castiel, Crowley, and Mary Winchester. However, the evil one has left a little gift behind to keep the boys company during his absence.
While possessing the body of the United States President, Lucifer impregnated the unsuspecting Kelly Kline and despite the protests of almost every angel in existence, the Nephilim (angel/human crossover) was born. Of course, Jack isn't a regular Nephilim, he's the first known example of a hybrid bred by an Archangel and was seen at the climax of season 12 having already grown into a young man. Try explaining all that to someone who's never watched the show.
With Jack's mother deceased and Castiel also seemingly defeated, the responsibility of watching over Jack naturally falls upon Sam and Dean Winchester - and Supernatural producer Andrew Dabb claims that their parenting experience will be a key element in the forthcoming season. Speaking with Entertainment Weekly, Dabb says:
“Last season was about the guys being kids, and this season is about being parents, to a degree. To have [Sam and Dean] confronted by this kid who is at once scary and charming gives us a chance to show a different side of the guys, and that’s always a great thing, especially 13 seasons in... The joke is that it’s My Two Dads, Hell Edition.”
Dabb is certainly correct in his belief that Sam and Dean taking care of Jack could bring out different sides to the two protagonists. Previous episodes have shown flashes of the Winchesters experiencing parenthood - the Shifter baby, Lisa's son Ben and Dean's grown-up Amazon child for example - but these have been relatively short-lived plot lines. Furthermore, Jack is the unique position of being an immensely powerful adult but with no experience of life on Earth. As such, seeing how the brothers cope with their new-found responsibility across the length of an entire season will undoubtedly be fascinating to watch.
However, this is Supernatural and there is bound to be a fair amount of conflict between Sam and Dean in season 13. A lot has already been made of whether of not Jack is inherently "good" or will turn out like his pitchfork-wielding old man. Kelly and Castiel firmly believed that Jack had the capacity for kindness but this issue is likely to become a sticking point between the Winchesters in the episodes to come.
Supernatural season 13 premieres tonight (October 12th) on The CW.