Shapechanger. The werewolf can use its action to polymorph into a wolf-humanoid hybrid or into a wolf (both of which are Large size), or back into its true form, which is humanoid and Medium sized. Its statistics, other than its AC and size, are the same in each form. Any equipment it is wearing or carrying isn't transformed. It reverts to its true form if it dies.

Keen Hearing and Smell. The werewolf has advantage on Wisdom (Perception) checks that rely on hearing or smell.

Reckless. At the start of its turn, the werewolf can gain advantage on all melee weapon attack rolls it makes during that turn, but attack rolls against it have advantage until the start of its next turn.

Improved Critical. The werewolf scores a critical hit on a roll of a 19 or 20.

Siege Monster. The werewolf deals double damage to objects and structures.

Multiattack. (Humanoid or Hybrid Form Only). The werewolf makes two attacks: two with its chains or club (humanoid form) or one with its bite and two with its claws (hybrid form).

Bite (Wolf or Hybrid Form Only). Melee Weapon Attack: +11 to hit, reach 5 ft., one creature. Hit: 12 (1d12 + 6) piercing damage. If the target is a humanoid, it must succeed on a DC 14 Constitution saving throw or be cursed with werewolf lycanthropy.

Claw (Hybrid Form Only). Melee Weapon Attack: +11 to hit, reach 10 ft., one target. Hit: 17 (2d10 + 6) slashing damage and if the target is Huge or smaller, it must succeed on a DC 17 Strength saving throw or be pushed 5 feet away from the werewolf.

Club (Humanoid Form Only). Melee Weapon Attack: +10 to hit, reach 5 ft., one target. Hit: 7 (1d4 + 5) bludgeoning damage.

Chains (Humanoid or Hybrid Form Only). Melee Weapon Attack: +10 to hit, reach 15 ft., one target. Hit: 9 (1d8 + 5) bludgeoning damage and if the target is a Medium or smaller creature, it must succeed on a DC 20 Strength saving throw or be restrained by the chains. The restrained creature can repeat the saving throw at the start of each of its turns, freeing itself and giving the werewolf advantage on attack rolls against it until the end of the next round on a success.

Wrathful Howl (Recharge 3-6). The werewolf unleashes a monstrous howl that blasts around it in a 45-foot radius. Each target that can hear the werewolf within that radius must make a DC 16 Constitution saving throw, taking 17 (5d6) thunder damage + 2 (1d4) wrath damage and be knocked prone on a failed save, or half as much damage and no other effects on a success.