The twist of the movie will be that Cooper's daughter is the real Big Bad.
- She's a vampire or a monster of some kind, and the reason Cooper kills people is to feed her.
Cooper's daughter is the real Big Bad, but there is not a supernatural twist.
- She's a garden variety sadist who has manipulated her father into imprisoning and killing people.
Lady Raven is The Man Behind the Man.
- Most of M. Night Shyamalan's work is overtly supernatural, and "Lady Raven" sounds like it could be the name of a supernatural creature of some kind. Whether knowingly or otherwise, the Butcher is fulfiling her orders - or she is the Butcher, but with underlings to do her dirty work - and the concert itself is a trap for some kind of summoning (such as an exorcism or a sacrifice).
