The exclusive clip comes from a Season 11 Blu-ray/DVD featurette called "The Winchester Mythology: Shedding The Light On The Darkness," and it's an interesting look into what inspired the team behind Supernatural to explore another complex sibling relationship. The plot was a natural extension of the Season 10 arc of the Mark of Cain that culminated in Death's death and the Darkness' release, but the reveal that she is actually the sister of God himself came as a surprise. God had been missing from Supernatural for a long time and was even presumed gone forever by his angels. It took the escape of his sister and her vendetta to destroy his creation to draw him out from the sidelines.

Considering that Supernatural has spent more than a decade examining the sibling relationship between Sam and Dean Winchester, the introduction of the conflict between God and the Darkness was a great way to both foil and highlight aspects of the Winchester boys' bond. God himself revealed that he needs his sister to remain alive, even if he had to keep them separate for the sake of the world he created. Actor Mischa Collins had this to say about God's rationale:

Chuck talks about it in terms of yin and yang and, you know, a balance in the universe.

Just as Sam and Dean seem to need and always come back to each other, God and the Darkness need each other alive in order for existence to continue. Of course, Sam and Dean's spats only occasionally result in an apocalypse. The God/Darkness battle had high enough stakes that the boys had to deal with everybody from demons to a witch to Lucifer himself. Luckily, Dean's ability to relate to Amara's frustration with her brother allowed him to talk her down from destroying the world. God and the Darkness ended the season on good enough terms. Unfortunately, the same cannot be said for both Winchesters. Sam was last seen being shot in the bunker, and Dean has a freshly resurrected mom to deal with when the show returns for Season 12.

The Supernatural Season 11 Blu-ray/DVD set will be released on September 6, 2016. You can order your own copy here, which features four more hours of bonus content, including what is sure to be another classic gag reel of gaffes and pranks galore. Supernatural returns to The CW for Season 12 on Thursday, October 13 at 9 p.m. ET. Check out our fall TV premiere schedule to see when your other favorite shows will be back on the airwaves in the near future.