Metatron has revealed that Darkness is God's sister! Supernatural season 11 episode 6 shocked fans, with the revelation. In the last chapter, Castiel tracked down a former scribe of God, and after a rather violent argument between the two, Metatron agreed to share the story behind Darkness aka Amara.
Metratron tells the Angel, "The truth will make the Bible thumpers head explode. They want their God to be finger snapping, all powerful creator. They want magic... Mary Poppins. What he did, creation.. that took work, took sacrifice. In order to create the world, God had to give up the only thing he had ever known. He had to betray, and sacrifice his only kin. The Darkness is his sister."
So, God betrayed Amara to create the world and her return makes for a big showdown between God and Darkness. In the same episode, Dean came face-to-face with Amara, who shared that she has returned to "settle an old score". Amara tells Dean, "There is a whole world for me to explore and I can practically taste it. Soon I will be strong enough to do, what I came here to do.. To settle an old score.. The oldest score."
So does this mean that Sam and Dean fighting against God's sister? This is a question fans have been seeking answers for.
Meanwhile, Misha Collins teased Castiel's objective and plans to defeat Darkness. Collins told Buddy TV, "Cas's number one objective at this point is to extinguish the Darkness in some way. For him, that ends up going very, very, very badly. As badly as-- I mean really badly."
He also revealed that Castiel will make another deal with the Devil to defeat this new threat. "In an effort to combat the Darkness, in a sense, Cas makes another deal with the Devil that becomes another one of those things that everyone probably knows is a bad idea, but he does it," the actor said.