Boar King - First Child of Nature

Charge. If the boar king moves at least 20 feet straight toward a target and then hits it with a tusk attack on the same turn, the target takes an extra 10 (2d10) slashing damage. If the target is a creature, it must succeed on a DC 18 Strength saving throw or be knocked prone.

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

Aura of Nature. The boar king is the first child of nature. Any beast creatures within 20 ft to the boar king and himself, gain the effect of the Barkskin and  Heal 6(d12) every turn. Furthermore, the boar king gains 3 extra AC against every kind of magic attack. 

Pride of the first Child. Boar kings are the first children of nature. The boar king cannot be charmed or be the target of the Charm Monster unless HP is less than 20. 

Hard Skin. The boar king is old and his skin is hardened. he has resistance to piercing, slash, and bludgeoning damage. 

 Pack Tactics. The boar king and his clan have advantage on attack rolls against a creature if at least one of the boar's allies is within 5 feet of the creature and the ally isn't Incapacitated.

Multiattack. the boar king makes two attacks. 

Tusk. Melee Weapon Attack: +11 to hit, reach 5 ft., one target. Hit: 27 (4d10 + 7) slashing damage.

Grunt(Recharge 5–6). The boar king grunt very loudly. Each creature in a 20-foot-radius sphere centered on that point must make a DC 15 Constitution saving throw. A creature takes 24(6d8) thunder damage and Stunned on a failed save, or half as much damage on a successful one and not be stunned. A creature made of inorganic material such as stone, crystal, or metal has disadvantage on this saving throw. The Stunned target must make a Constitution saving throw at the end of each of its turns. On a successful save, this stunning effect ends.

Retreat. When the boar king is attacked, He moves 10 ft away from the attacker without provoking the opportunity attack. If the way is blocked by a hostile creature, this reaction cannot be used.