Diego Cohen’s Mark Of The Devil (La Marca Del Demonio) is one of those movies that wants to be Lovecraftian but isn’t (despite the numerous times various deities of his Cthulhu Mythos are mentioned) and is in fact a typical possession story.
And that’s okay because it’s not a terrible movie though I would have enjoyed it more if it had eschewed the ‘Cthulhu’ angle entirely.
And by the way, did you know that according to Wikipedia Cthulhu has a ‘secret daughter, Cthylla!? I have read a lot of Lovecraft and have never once encountered that particular deity, so take that how you will.
As I said, it’s not terrible and actually has some pretty interesting ideas to ply though I’d wish it had more faith in them.
Mark Of The Devil is available on Netflix and is a Mexican production.