Alpha Wereboar

Shapechanger. The alpha can use its action to polymorph into a boar-humanoid hybrid or into a giant boar, 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.

Charge (Boar or Hybrid Form Only). If the alpha moves at least 15 feet straight toward a target and then hits it with its tusks on the same turn, the target takes an extra 7 (2d6) slashing damage. If the target is a creature, it must succeed on a DC 19 Strength saving throw or be knocked prone.

Relentless (Recharges after a Short or Long Rest). If the alpha takes 20 damage or less that would reduce it to 0 hit points, it is reduced to 1 hit point instead.

Pack Leader. The alpha's allies have advantage on melee attack rolls against any hostile creature within 5 feet of the alpha and the alpha isn't incapacitated.

Alpha's Presence (Hybrid Form Only). Any lycanthrope that starts its turn within 30 feet of the alpha's Hybrid form must succeed on a DC 19 Wisdom saving throw or be forced to use their reaction to transform into their own Hybrid form.

Legendary Resistance (3/Day). If the alpha fails a saving throw, it can choose to succeed instead.

Multiattack (Humanoid or Hybrid Form Only). The alpha makes three attacks, only one of which can be with its tusks.

Maul (Humanoid or Hybrid Form Only). Melee Weapon Attack: +11 to hit, reach 5 ft., one target. Hit: 14 (2d6 + 6) bludgeoning damage.

Tusks (Boar or Hybrid Form Only). Melee Weapon Attack: +11 to hit, reach 5 ft., one target. Hit: 20 (3d6 + 6) slashing damage. If the target is a humanoid, it must succeed on a DC 19 Constitution saving throw or be cursed with wereboar lycanthropy.

The alpha 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. The alpha regains spent legendary actions at the start of its turn.

Intimidating Stare. The alpha stares at a single creature within 30 feet of it, that creature must succeed on a DC 19 Wisdom saving throw or be frightened of the alpha for 1 minute. The target can repeat this saving throw at the end of each of its turns. 

Squeal. The alpha lets out a deafening squeal, each creature within 20 feet of the alpha must succeed on a DC 19 Wisdom saving throw or be deafened.

Relentless Charge (Costs 2 Actions). The alpha charges in a straight line, up to its movement, making a tusk attack against any creature in that line, on a hit, the creature must also succeed on a DC 19 Strength saving throw or be knocked prone.