Monastic Tradition: Way of the Rising Tide

Thalassic Guidance

When you take this monastic tradition at 3rd level, you gain the ability to to breathe underwater, and you have a swim speed equal to your movement speed.

Crashing Wave Technique

At 3rd level, when you make an unarmed strike, you can spend 1 ki point to channel watery energy into your attacks. Your reach with your unarmed strikes increases by 10 feet for that action, as well as the rest of the turn. On a hit with this attack, the target must succeed on a Strength saving throw or be knocked prone.

Mantle of the Whirlpool

At 6th level, as a bonus action, you can spend 3 ki points to magically wreathe yourself in swirling water. For 1 minute, you gain the following benefits:

Area in a 15 ft. radius around you becomes difficult terrain for all creatures other than yourself.

When you knock a creature prone with your Crashing Wave Technique, you can push it back a number of feet equal to your Unarmored Movement bonus.

Ranged attacks that pass through the whirlpool are rolled with disadvantage.

You can dismiss the whirlpool as a bonus action. It is dispelled automatically if you are knocked unconscious.

Primordial Step

At 11th level, you have fully adapted to your elemental calling. You are resistant to fire damage, and you ignore any of the drawbacks caused by a deep, underwater environment.

In addition, when you are standing in water or rain, as a bonus action you can teleport up to 60 feet to an unoccupied space you can see that is also in water or rain. You then have advantage on the first melee attack you make before the end of the turn.

Wrath of the Tempest

At 17th level, while under the effects of your Mantle of the Whirlpool, you can use your action and 4 ki points to send a surge of crackling lightning throughout your whirlpool.

Each creature within 15 ft. of you must make a Dexterity saving throw, taking 6d10 lightning damage on a failed save, or half as much on a successful one.