The first time we hear about the Darkness directly, it’s from Charlie’s research into the Book of the Damned (10×18).
Okay, here’s what I’ve learned so far. About 700 years ago, a
nun locked herself away after having visions of darkness. After a few
decades squirrelled away by herself, she emerged with this. Each page is made out of slices of
her own skin written in her blood. I told you, it’s eekish. According to the notes I found, it’s been owned and
used by cults, covens, and the Vatican had it for a while. There’s a
spell inside that thing for everything. Talking some black mass, dark
magic, end-of-times nastiness. As far as what language it’s written in,
I’m thinking it’s some kind of…uh…The first time we hear of the darkness, it’s already being associated with women. The Book of the Damned, which would open the key that had locked the Darkness up, was written by a woman who, most likely, had spent much of her life solely with other women.
I also noticed that the book is made out of self-sacrifice. The nun didn’t kill someone else to make the book – instead, she took the time (decades) to do it using her own skin, her own blood. She must have done it a page at a time, then waited until her body was healed enough to do the next page. It was a slow, painful process of dedicating her life to this, not anything quick or easy. The key that opened the lock to the Mark of Cain was made out of self-sacrifice. And, potentially like the Darkness herself, the Book was said to be indestructible (and, so far, that appears to be true).
This self-sacrifice is emphasized again in the next episode. We see that Sam is required to bleed into the lock holding the Codex that will translate the Book. We also learn that the person who wrote the Codex that can translate the Book was a woman – Nadya, a grand coven witch who was murdered by the Men of Letters, her works stolen.
Susie, the reluctant and semi-unknowing guardian of the Codex’s current lockbox, is killed during Sam’s retrieval of the Codex. The next episode, one woman is sacrificed for the cause while yet another has been imprisoned. In season 10, Sam appeared to follow closely in the footsteps of the Men of Letters – women do the majority of the work, but then a man reaps the reward.