I remember watching a movie where a group of people go to a house that sits alone in the woods, for a vacation or something.
The thing is, there's this evil, possessed person inside a locked door. Somehow he comes out and he tries to kill the people that are there on vacation. Once a person shoots and kills the possessed person, the evil spirit goes inside the person who killed it.
The ending of the movie was that a person's loved one gets possessed, so he locks her up in the room and he starts to live in that house.
It is a very similar movie to Don't Kill It. But I watched this like maybe in 2013-2015. I think Don't Kill It is a copy of it with one difference: that in Don't Kill It... there's a clear hunter who hunts all... where in the movie which I'm looking for they'll only have a vague idea on how to kill it until the end.
Even in the end, the protagonist locks up the possessed one in the room and lives in the house until:
Maybe he gets possessed
Kill the possessed in the room and lock himself up inside the room without getting out