Way of the Breathtaker

Those who choose the path of trying to discover the secrets of breathing must train hard and steadfast. Through generations the secrets of breathing techniques is passed down to upcoming and promising monks. The scholars set one goal, and one goal only, to free the world of evil deed and for that their blade and their history reflects their pride on the battlefield. Though breathing may promise calmness and peace, the blade of the breathtaker strikes deadliest if underestimated. 

Breathing Techniques

As of choosing this fighting archetype at level 3 you have mastered the secrets of channeling power through breathing. Therefore, you have a pool of breathing points which is defined by your constitution modifier plus your proficiency bonus. Those points refill after a short rest.
Also you choose which school of breathing technique you want to follow water or lightning. After choosing your breathing technique origin, you are granted three skills which can be activated by spending breathing points.

Lightning Breathing Technique

You are one with wild low of lightning, which brings forth breathing techniques:

Lightning Breathing Technique: Flash
After spending 3 breathing points you become as quick as a flash which gives you the ability to teleport an unoccupied space within 30 feet, which you can see. This feature can be used as a bonus action. 

Lightning Breathing Technique: Lightningclap
Your strike is harsh and true. On your next attack hit you deal 2d6 extra lightning damage. Using this feature costs, you one breathing point. 

Lightning Breathing Technique: Piercing Light
You strike your sword against a creature with lightning force. The attack resembles a lightning which just stroke in front of your eyes, forcing the enemy to roll a constitution saving throw against your breathing technique safe dc on hit. If the roll fails, the creature is blinded until your next round. The creature also takes 2d6 lightning damage if it failed its roll and half the damage on a safe. This technique consumes 2 breath points. 

Keen Sense:
Spending one breathing point gives you advantage on your next perception roll (has to be used within one minute), as you trained your senses to near perfection in location threats.

Water Breathing Technique

You mastered the calm but deadly flow of water. As so the following skill are set in your repertoire:

Water Breathing Technique: Dead Calm
You become nimble and are able to move as fluidly as water. Move up to 30 feet. While moving opportunity attacks have disadvantage against you. If you chose to stop near a target of your weapon attack range, you roll for an attack and on hit the target takes 2d8 cold damage. This breathing technique requires you to spend three points and counts as an action.

Water Breathing Technique: Surface Slash
Your next weapon attack brings forth the force of tides. Therefore, your attack deals additional 2d6 cold damage on hit. Using this technique requires you to spend one breathing point.

Water Breathing Technique: Waterwall
Consuming 3 breath points, you slash your blade in chosen direction in order to create a magical water wall. The wall is 10 feet long and five feet wide and every creature who passes through or ends its round within the wall takes 2d6 cold damage, as the force of the currents damages their body. The wall vanishes after 1 minute or if you lose concentration in maintaining the breathing. Because you are already in a concentrated mode, you can use other techniques but no other which requires you to maintain concentration.

Keen Sense:
Spending one breathing point gives you advantage on your next perception roll (has to be used within one minute), as you trained your senses to near perfection in location threats. 

Superior Swordsmanship

Years of year of practicing is paying off. While you are discovering the secrets of breathing, your get more proficient with the katana (rapier). As so you get the proficiency with the rapier weapon.

Nichirin Blade

As you hone your sword technique more and more, you learnt to infuse your breathing technique into your weapon attacks. Therefore, reaching level 7 damage dealt with a rapier or a short-/longsword is considered magical for the purpose of overcoming resistances.

Improved Breathing Techniques

Your training is paying off, which lets you learn two additional breathing techniques of your chosen breathing path.

Improved Lightning Breathing Technique

Lightning Breathing Technique:

 

Lightning Breathing Technique:

Improved Water Breathing Techniques

Water Breathing Technique: Holy Water
After spending 2 breathing points you heal yourself for 2d8+ your proficiency bonus because you mastered the curing effects of water breathing. 

Water Breathing Technique: Whirlpool
You swing your Blade around yourself creating emitting a small wave which is 5 feet long in all directions. Every creature within this range takes 3d6 cold damage on failed dexterity safe or half as much on a saved one. This technique requires an action and 3 breathing points to use.

Total Concentration Breathing: Constant

While in this state you don’t need to expand any breathing points and can use your breathing techniques at will. This state lasts 1 minutes, until you fall unconscious or die. The use replenishes after a long rest. 

Mark of the Breathtaker

You have awakened the deepest secret of breathing and the ultimate power which comes with it. As your mark is activated you gain the following advantages for the next 2 minutes or until you fall unconscious: 

• movement speed is increased by 15 feet
• You won’t trigger any opportunity attacks, as you are too fast to catch for an eye while moving (if you have chosen the water breathing technique, you instead teleport up to 10 feet to a position of your choice which isn’t occupied once per round)
• Your attacks become stronger; therefore, every attack deals additional d8 plus your strength modifier bonus damage (damage type depends on the breathing path chosen)

The mark can be used once per long rest and is activated with a bonus action.