Blackfang

Shapechanger. Blackfang can use his action to polymorph into a wolf-humanoid hybrid or into a dire wolf, 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.

Darkvision. Being imbued with the senses of the largely nocturnal wolf, Blackfang has superior vision in the dark. It can see out to 60 feet in dim light as if it were bright light, and in darkness as if it were dim light. He can't discern color in darkness, only shades of grey.

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

Pack Tactics. Blackfang has advantage on an attack roll against a creature if at least one of the his allies is within 5 feet of the creature and the ally isn't incapacitated.

Pack Leader. Blackfang's allies have advantage on melee attack rolls against any hostile creature within 5 feet of Blackfang, as long as Blackfang isn't incapacitated.

Packleader's Presence. If any lycanthrope members of Blackfang's pack start their turn within 30 feet of the Blackfang's Hybrid form, they must succeed on a DC14 Wisdom saving throw or be forced to use their reaction to transform into their own Hybrid form.

Legendary Resistance (2/Day). If Blackfang fails a saving throw, he can choose to succeed instead.

Bloodied

When bloodied at 49 HP, Blackfang has the following features:

Trigger Ability: Frenzy. When first bloodied, Blackfang can make up to three attacks with his claws against any creature within range as a reaction.

New Ability: Bloodlust. While bloodied, Blackfang deals one extra die of damage with his melee weapon attacks against other bloodied creatures.

Multiattack. Blackfang makes three attacks: one with his bite and two with his claws.

Bite (Wolf or Hybrid Form Only). Melee Weapon Attack: +7 to hit, reach 5 ft., one target. Hit: 13 (2d8 + 4) piercing damage. If the target is a humanoid, it must succeed on a DC 14 Constitution saving throw or be cursed with werewolf lycanthropy.

Claws. (Hybrid Form Only). Melee Weapon Attack: +7 to hit, reach 5 ft., one creature. Hit: 11 (2d6 + 4) slashing damage.

Blackfang can take 3 legendary actions, choosing from the options below. Only one legendary action can be used at a time and only at the end of another creature's turn. Blackfang regains spent legendary actions at the start of his turn.

Claws. Blackfang makes one attack with his claws.

Feral Leap (Costs 2 Actions). Blackfang leaps up to his speed to a space adjacent to an enemy, without provoking opportunity attacks. The enemy must succeed on a DC 15 Strength (Athletics) or Dexterity (Acrobatics) check or be knocked prone.

Piercing Howl (Recharge 5-6, Costs 3 Actions). Blackfang lets out a terrifying howl, rallying his allies and striking fear into his enemy's hearts. Up to 3 allies within 30 ft. of Blackfang that can see or hear him can use their reaction to make one melee weapon attack against another creature within 5 ft. of them. Enemies within 30 ft. of Blackfang must succeed on a DC 14 Wisdom saving throw of be frightened until the end of their next turn.