Path of the Tidebringer

Not all barbarians hail from land-dwelling peoples. Some are corsairs, pirates, or nomadic people who frequently travel the seas. Those barbarians learn to master movement and resilience from the rocking of the ocean tides, the vicious waves that sweep lesser men to their doom, and from fighting and charging through rough waters and damaged ships. They can harness the force of the tides in their rage, unleashing blows as merciless as the seas themselves.

Crashing Force

At 3rd level, you can channel the fury of a crashing wave upon your enemies. During your rage, when you move at least 15 feet and then attack a creature, the first attack you land against that creature does an extra 1d8 damage.

At 11th level, this damage increases to 1d12.

Unyielding Current

Also at 3rd level, the fortitude and resolve your rage grants you lets you charge through harsh ground or rough seas. When you use the Dash action while raging, you can move up to your movement speed through difficult terrain or water without reduced movement. If you cross through difficult terrain or water while using the Dash action, the exertion prevents your rage from ending early if you don't attack a creature or take damage before your next turn.

Stout as the Shoals

At 6th level, you can stand strong against the mightiest blows or waves. You have advantage on saving throws against effects that would physically move you and/or knock you prone, and on a failed saving throw against such effects, you can reduce the distance you are moved by up to half the distance (to a minimum of five feet).

Raging Riptide

At 10th level, your movement while raging carries with it the merciless force of the seas. When you move, creatures of your choice that you move within five feet of must make a Strength saving throw, against a save DC of 8 + your Strength modifier + your proficiency bonus. On a failed save, the creature takes damage equal to your rage damage bonus and cannot make attacks of opportunity against you until the end of your turn. On a successful save, the creature takes half as much damage, and if they attempt an attack of opportunity on your turn, the attack roll is made with disadvantage.

Monsoon

At 14th level, you can strike with the force of a great tidal wave. As an action while raging, you strike all creatures in a 15-foot cone in a direction of your choice. All creatures in the affected area must make a Strength saving throw, against a save DC of 8 + your Strength modifier + your proficiency bonus. On a failed save, the creature takes 2d12 damage + your Strength modifier, and is knocked back five feet and rendered prone. On a successful save, the creature takes halved damage and is not moved or knocked prone.

You can use this ability once per rage.