Curse of Strahd
Lycanthropes capable of shape shifting from humanoid to werewolf form. Keen sense of smell and hearing. Usually travels in packs. Presumably chaotic evil in nature. Faster than normal speed. Normal attacks from physical damage don’t seem to be as effective against werewolves.
From a charmed werewolf the party discovered that the werewolves live in a den just west of Lake Zarovich hidden in the woods. There’s a single pack with competing leadership and the clan kidnaps children and makes them fight to the death to determine who they will convert to become new werewolves for the clan.