Charge. If the zephyr boar 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 9 (2d8) slashing damage. If the target is a creature, it must succeed on a DC 14 Strength saving throw or be knocked prone.

Relentless (Recharges after a Short or Long Rest). If the zephyr boar takes 15 damage or less that would reduce it to 0 hit points, it is reduced to 1 hit point instead.

Warding Wind. Whenever the zephyr boar uses its Whirlwind ability it gains the benefits of the Warding Wind spell (no concentration) until the end of its next turn.

Tusk. Melee Weapon Attack: +6 to hit, reach 5 ft., one target. Hit: 11 (2d6 + 4) slashing damage.

Whirlwind (Recharge 4–6). 

Each creature within 10 feet of the zephyr boar must make a DC 14 Strength saving throw. On a failure, a target takes 16 (3d8 + 4) bludgeoning damage and is flung up 20 feet away from the zephyr boar in a random direction and knocked prone. If a thrown target strikes an object, such as a wall or floor, the target takes 3 (1d6) bludgeoning damage for every 10 feet it was thrown. If the target is thrown at another creature, that creature must succeed on a DC 14 Dexterity saving throw or take the same damage and be knocked prone.

If the saving throw is successful, the target takes half the bludgeoning damage and isn't flung away or knocked prone.

Dash. The zephyr boar can move up to its speed as a bonus action.

Stomp. Melee Weapon Attack: +6 to hit, reach 5 ft., one target that is prone. Hit: 15 (2d10 + 4) bludgeoning damage.