"I do not believe this darkness will endure"
- Faramir, Lord of the Rings: The Return of the King
So I'll be honest here, I have never seen Lord of the Rings, but this quote was on my daily quote calendar (once in a while I will pull from this, actually a lot of time I pull from this). Darkness can't endure, it never does - because the story is not over until good wins. (I sound like Henry right now). In any movie there is always a part where the darkness is on top, but never wins. Darkness may win a battle or two, but will never win the war.
Even in Once Upon a Time, which is what this quote reminded me up, the darkness has had it's moments on top. Especially now (**spoiler**), with Emma, the savior, becoming the new Dark One.
Not gonna lie, when I saw this quote my mind went straight to that scene when Emma was consumed by darkness, and we all know going into Season 5, that it will not endure.