A small summary of this movie is that it was a dark realistic film over the Catholic church's historical tries to take away moral corruption. It was also seen as demonic sorcery and in response they burned women accused of witchcraft. It follows this group of six girls in 1600's Basque Country that were accused and improsened for practicing the Witch's Sabbath and conversing with Lucifer.
The movie was a mix of traditional folklore while maintaining a feminist view. The men were totalitarian judges that lived in superiority and were threatened by the group of women. It was an interesting film and it really puts the audience in the shoes of those that were victims of witch hunts. It's interesting that each of the girls interpretations are in the film. They all had to come together to try and survive against the men, at one point they try and convince them that they truly are witches. The women are made to do these satanic rituals while the inquisitors watch. The lead, Amaia Aberasturi, has to create these stories based on true life and describe Lucifer based on imagination while singing this incantation that scales higher and higher making direct intense eye contact.
The music mixed with the lighting plays a big role I'd say when it comes to generating the fear that we see. We don't really see much of supernatural elements but just the inquistition of witchcraft. Because of the photography and the lighting it makes the gaze hypnotizing and the film have a magical feel even without seeing the witchcraft first hand.