When Ed and Drew (Shannon Kook) then later use a map of railways to figure out where a train might be passing at midnight, they deduce it is at the Kastner house. So we end up with a grand showdown where Ed and Lorraine face off against the Kastner daughter, who is now even going so far as to murder her own father, a feeble failure of a priest who apparently wasn’t even aware she was on his property for at least several months now.
Afterward Ed is possessed by the demon and goes the full Jack Torrence by picking up a sledgehammer and planning to murder his wife. But through the power of love, Lorraine gets through to Ed’s possessed heart, freeing him from demonic influence and allowing Ed to smash the witch’s altar, which for some unexplained reason also frees Arne—who’s about to kill himself back in prison—from the demon.
With the summoned demon no longer forced to do the bidding of the Kastner daughter, it decides to take her soul back to Hell with it. Arne is spared further demonic possession, and suddenly five years in prison doesn’t look so bad when compared to an eternity in Hell.
Frankly, the ending, like much else with The Conjuring 3, left this writer more than a bit underwhelmed. The idea of the villain being a daughter borne out of the dangerous study of the occult could’ve created a spooky narrative that hit closer to home for the Warrens. After all, they never burn their own creepy mementos, which have bedeviled their daughter Judy on more than one occasion onscreen, as seen in both the original The Conjuring and Annabelle Comes Home. A movie about the pair seeing a danger to their daughter reflected by the Kastners, and one that which perhaps incorporated the whole Warren family solving the case, might’ve made for a more emotionally satisfying movie. As with the first movie, we’d once again have a story of two families, with the Warrens seeing a more shadowy contrast in the Kastners.
It would’ve been more interesting than the plot in its current form, which appears a bit like a lazy riff on the demon-worshipping cult in Hereditary, arguably the most popular supernatural horror movie to be released since The Conjuring 2. The Conjuring 3, meanwhile, also was done no favors by its rushed narrative turning Arne and the Glatzel family into largely ciphers, depriving the audience of much cathartic investment until Ed starts getting possessed himself.
Granted, the real-life Judy Warren had nothing to do with this case and there never was a Father Kastner, so turning that into the focus of the movie would be stepping even further away from the main franchise’s increasingly dubious “based on a true story” shtick. But we’re so far from true stories, why quibble about that now? The Annabelle doll was never associated with Satanic cults or the Manson family, it never Night at the Museum’d Judy, and Ed did not have a heart attack during the Glatzel exorcism. In fact, Arne was not sentenced to five years.