The Stranger (2015)

I assume there are a lot of movies with that title, although IMDb only lists this and the 1946 one with Orson Welles and Edward G. Robinson, so I put the year up as well.

A guy with blood that can heal and an aversion to sunlight arrives in a town seeking a woman named Ana. He learns from a teen named Peter she's dead, then runs afoul of a drunk asshole, one who is protected by his cop father. Peter's attempts to help the man only drag him and his mother into a cycle of threats, torture, and attempted murder. The stranger's blood can heal you, but at a cost.

I was expecting something more like Storm of the Century, or Needful Things. Not precisely along those lines, but a more deliberately malevolent presence. Martin doesn't seek out the trouble, he doesn't really care what happens to him. It's other people who decide they just have to stab him, or try to save his life. He warns them not to mess with his blood, they don't listen. Then he has to try and clean up the mess.

There's a theme of what parents will sacrifice for their children. Ana ultimately gave her life to bring Peter into the world. Martin figures the best he can manage is to stay far away from Peter. Monica, the nurse who has actually raised Peter is doing her best, but is out of her depth once they're faced with people don't give a shit about how you "should" behave. The cop keeps protecting his worthless shitbag of a kid, even to the point of shooting people, or lighting them on fire to try and get information, in addition to generally abusing the authority of his position.

(Not a movie with a positive view of cops. They're either crooked as hell, mindless thugs, or the few that follow the rules are spineless, useless imbeciles.)

I did wonder if, at some point, this cop would decide he'd thrown away everything for this son who had accomplished nothing but hurting people for no good reason and decide enough's enough. But it's his kid, that's not going to happen. He figures any act on his part is justified for this kid. Which explains a lot about how the kid wound up a complete shithead, but I imagine that blindspot is common among parents.