Werewolf uses the magic within the user to determine its strength. The stronger the wizard, the stronger the wolf, to become a magical tank of destruction that all should fear.
Weakest during transition, otherwise a powerhouse like no other.
Isn't fond of Wizards marrying Muggles, doesn't trust them, this leads to him being overly critical of their children???
IT'S A MISCONCEPTION to think unforgivable couldn't be blocked by normal means. The only reason it got such a reputation is that there were strong wizards firing strong spells against weak wizards.
You have to be strong, and you have to want to survive as much as they want to kill you to block it???
.....
Werewolf in Harry potter
Natural born occulmency, allowing control of his Werewolf form, and decent immunity to the torture curse given his painful experience with his transformations, and decently immune to magic once transformed, because a trained wizard with full faculties can harness his magic in werewolf form like a protective shell allowing him to hunt unimpeded.