A vietnam vet, who when under extreme stress transforms into an animal matching the situation, the main character was
the only survivor of his unit (I assume this was the first movie) and he returned to the US, living alone in the woods with a
pack of dogs.
however the person he left behind who came after him for revenge (I assume this was II) is not actually dead, but transformed
to a dog himself, and is waiting for revenge, hiding in with the pack
There was something else as well, with the main character having to leave his haven in the woods, and return to society
to use his powers to help some woman with some case that the police refuse to believe, and returning home to not only
find that something has been killing his dogs, but that the case he thought he put to rest in the city is coming back to
haunt him. (perhaps the woman was not in the right in whatever happened, and whoever he got revenge against is
coming after him?)
Hmmm - sounds like this should be #4 and not #3, but I remember the title clearly.