The The Conjuring: The Devil Made Me Do It ending left viewers with a few questions, especially when it came to having The Conjuring 3 demon origin explained. Making sequels is a grueling task because the expectations are high and, for an already successful horror franchise like The Conjuring universe, the pressure is even more immense. In The Conjuring 3, The Warrens return to investigate David Glatzels possession and find a curse and an occultist behind the boys strange behavior. This Conjuring villain is different from previous cases.
https://screenrant.com/conjuring-3-movie-ending-explained-demon-origin/