Werewolf

A werewolf is a savage predator that can appear as a humanoid, or in a terrifying hybrid form—a furred and well-muscled humanoid body topped by a ravening wolf’s head.

Shapechanger:  The werewolf can use its action to polymorph into a wolf-humanoid hybrid or back into its true form, which is humanoid. Its statistics, other than its AC, 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 + 4) checks that rely on hearing or smell.

Damage Immunities: Bludgeoning, Piercing, and Slashing from Nonmagical Attacks that aren't Silvered

A humanoid creature can be afflicted with the curse of lycanthropy after being wounded by a lycanthrope, or if one or both of its parents are lycanthropes. A remove curse spell can rid an afflicted lycanthrope of the curse, but a natural born lycanthrope can be freed of the curse only with a wish.

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

Bite (Hybrid Form Only). Melee Weapon Attack:  +4 to hit, reach 5 ft., one target. Hit:  6 (1d8 + 2) piercing damage. If the target is a humanoid, it must succeed on a DC 12 Constitution saving throw or be cursed with werewolf lycanthropy.

Claws. (Hybrid Form Only). Melee Weapon Attack:  +4 to hit, reach 5 ft., one creature. Hit:  7 (2d4 + 2) slashing damage.

Known werewolves:

 * Sian
 * Arwen
 * Packmaster