Pretty sure this was set in Ireland or England. Probably between 2010 and 2018 release.
A mother who is revealed to have some magic abilities keeps her son alienated from other kids. Especially girls near his age. They live in an assisted housing complex.
At one point a social worker comes to check up on her. The conversation devolves and the worker threatens to take her son away. The mother verbally curses the social worker, and she becomes confused and lost. The worker is unable to remember where she is or what she is doing. The mother also has some kind of standing hex so people specifically looking for her and the sons apartment just can’t see the door or the address.
It then shifts to a man who is seeking favor from a group of people that live in campers/caravans out in a forest clearing of sorts. He wants them to grant him some type of powers. They eventually agree, and the man has to get inside one of the campers and get a type of ritualistic tattoo. It is later implied this lets him transform into a beast.
The man is assigned a companion by the camper people that drives him into a more urban setting. They head into a pub with just one or two patrons. One of the guys in the pub is said to be some type of local elder, and they seek permission from him to allow the man with the tattoo to “hunt” in his territory for the boy. I think the man is the brother of the sons father and blames the son for his brothers death.
Throughout the movie the man with the tattoo and his assigned companion find crows/birds and kill them. This somehow lets them divine the location of the boy and the mother. Each bird kill drawing them closer.
There are very dark scenes throughout where a heavily shadowed beast murders several people. It is implied this is the tattooed man in his quest to find the boy and mother.
The boy meets a girl his age, to the mothers severe disapproval. Eventually it is revealed that the boy is cursed and is a monster himself. I guess the onset of puberty and hormones, exacerbated by his new lady friend draw this beast out of him in the finale of the movie. There is a final confrontation, I think the tattooed man kills the mother, and the boy transforms killing the tattooed man and his lady friend.