The Rite is an exorcism film, based on a nonfiction book, also called The Rite. The film stars Anthony Hopkins as an exorcist, but you don’t just have a demonic possess movie with Hopkins and not have him get possessed, so, after freeing one woman, Hopkins is possessed, and the protagonist must help him out.
As befits a book based on a non-fiction account on the revival of exorcism educatin at the Vatican, The Rite captures many elements of demon lore: signs, behaviors, names, references, and portents, there is a lot to see.