Loved it, can we discuss the ending?
Possible explanation.
The old woman coming back from her own death and saying "it is misguided trying to fight me" probably means she represents Dogma. Timeless and immortal, everyone looks to her for authority and guidance. Dogma has the power to silence people, as seen in that supernatural scene where she literally tears out Eleanor's vocal chords. Even when there's seemingly nobody left and Mary begs her father to speak up, he gets shot before he can open his mouth. Dogma also blinds people to reason, like the old woman blinded Mary.
Which brings me to the book that everyone reads from. The father fears the book. Eleanor and Mary read it as a work of irony and biting cynicism. The old lady interprets it literally. Possible metaphor for how Christians see the Bible. Or is it a reference to "God creates enemies to perform his good" - the same book giving Mary and the old lady opposing ideas on religion?
What about the black finger? What does that mean? I'm not a Christian so maybe I might have missed some of the less obvious motifs.