Japanese Animated movie?

I need to know the name of this movie, I remember it being definetly a
Japanese Animated Movie, it was set in these dark woods or a jungle or
something I think there was animals but I'm sure I remember it being
something to do with evil spirit animals or something but I'm starting
to remember bits about it being a boy or girl (most likely girl) who
lived in the woods/forrect/jungle (whatever it was) the movie was very
dark from what I remember but I have to know the name? The animals
would have been like wild pigs or something