This is it fans, the finale fight pitting the most powerful beings in all of existence against each other, with Sam and Dean Winchester caught in the middle. This season of Supernatural has been exceptional, for the reason that they have expanded the lore of God, his Angels, and the truth that our lord and savior wasn't alone when he created the universe we live in. There was his sister, Amara, who was the darkness when God (Chuck) balanced her with his light.
What we will find out is what fate will befall Dean Winchester in regards to his 'bond' with Amara. She intends to absorb Dean within her being, so he can roam boundless for all eternity while she floats in nothingness inside God's sister.
Talking about God, Chuck intends to enlist all of the host of Heaven, as well as the legions within the bowls of Hell to defeat his very pissed off sister. This may be the best end game story of all time, and to show how great SUPERNATURAL still is, that is a comment often said for eleven years. As always, the boys are in for a fight.