“It’s not an infection. She says it’s a mirror. She’s showing us all the truth. The light was just a lie.” (”Don’t Call Me Shurley” 11×20)
Mirroring between dark and light also occurs strongly in Robbie T’s earlier episode 10×11 “There’s No Place Like Home”, when Charlie is split into Dark Charlie and Light Charlie.
The solution was a merge.
Charlie (speaking of the Wizard in 10×11)
“He used the inner key of Oz. It opens a door to your soul and lets the darkness out. Uh, we’re still connected physically.”
On a cosmic level, Dean has surely become the key, thanks to him being the last bearer of the Mark of Cain. Removal of the Mark from Dean resulted in the release of the Darkness, to whom he is now “bound” in some fashion.
Which would be why Amara intends to spare Dean amongst all the beings of creation.
Question is – can a merge between God and the Darkness (which I really hope proves to be the solution) take place without the destruction of the key?
Hearseeno 