Oh, antagonistic is a good word. They are not good dogs, and calling them that could cause a fight. Some don't even like humans and would rather kill them than bite them (some are born, some are bitten, y'know- flexibility and all that).
Antagonists I can do. Not sure that the island needs to become werewolf heavy (that's a horror movie in and of itself) though, but werewolf isn't a requirement.