Blade Dancer

Fighting is fighting, Blade Dancing is pure joy. Enemies fall around you, furthering your love of the dance. You trip one, decapitating him on the way down, suddenly a flip, the enemy isn't sure how you got behind him. You strike again, blood flies; you love it. 

You move about the battlefield so gracefully, your enemies can't seem to hit you. A dodge, a counter attack, another dead foe. No one is watching, but you feel the need to bow. After all, what you just did was art; like a performance, a dance, a beautiful execution. 

The Dance Never Ends

Starting when you pick this subclass at level 3, you can use a Bonus Action to use Dash, Disengage, or Dodge. If you move after this, opportunity attacks made against you are at disadvantage. You can use this a number of times equal to your DEX mod per short or long rest. 
Your critical strikes allow you to attack with your offhand weapon, if it has the light property, without using a bonus action. This attack cannot use performance points and critical strikes do not allow more attacks.

Putting on a Show

At level 3 when you pick this subclass, you gain performance points to fuel your attacks.
Your Performance Points total is equal to you level as a Fighter. All points are regained after a short or long rest.
Saving throws against your abilities are equal to 8+proficiency+DEX Mod.
You may pick two Dance Moves at level 3. You gain 1 more at levels 7, 10, and 15.
Every attack action can only benefit from 1 Dance Move. Dance Moves must be declared for use before making the attack roll.

After picking this subclass at level 3, you can spend 8 hours of downtime creating and training with the Chain Blade. Creation of the Chain blade takes 10ft of chain and two bladed weapons. This weapon acts as two blades weapons connected by a 10ft chain at each hilt. The weapon has reach to 10 feet, but due to the nature of the weapon you can adjust your hold and use it  within 10 ft without disadvantage. It is considered a Dex weapon and uses your Dex modifier for hit bonuses. The main blade is larger and deals 2d4+Dex mod damage. The off hand is a smaller blade and deal 1d4+Dex mod damage.
The weapon is considered a martial, special weapon. Anyone can use the weapon, but will need to train with it, similar to learning a new weapon proficiency. 
Each blade of the chain must be upgraded separately, a +1 bonus to the main hand does not upgrade the offhand. 
At level 15 as a fighter in this subclass, you have gained exceptional skill in the Chain Blade. You can spend 8 hours of downtime and two bladed-weapons, to upgrade your Chain Blade. The main hand now does 2d6+Dex mod, and the offhand deals 1d6+Dex mod.

Deadly Flourish, 3 performance points

You focus on your blade as it takes in natural energy. Make a single attack roll, choosing one damage type. Your weapon's damage is changed to the chosen type, and you deal an additional 1d6 damage for that attack. This attack counts as magical for overcoming resistances and immunity.
The additional damage die increases to 1d8 at level 7, 1d10 at level 10, and 1d12 at level 15.

Distracting Strike, 1 performance point

You make a special weapon attack. On a hit, you feint with your main hand, and strike with your offhand weapon instead, catching them off guard. The target has disadvantage on it's next attack against you.

Grand Finale, 1-6 performance points

If you move at least 10 feet towards and enemy you can jump over it, provided its size is medium or smaller. As you do make an acrobatics check vs the targets Dex save. You may expend a number of points up to your Dex modifier to deal 1d6 weapon damage per point expended. If they fail the save they take full damage and are knocked prone. On a successful save they take half damage and are not knocked prone. This counts as an attack action, but using it does not allow you to benefit from any extra attacks you may have left. This can only be used once per round.

Precision Strike, 1-6 performance points

Make a single attack roll. You may expend a number of points up to your Dex modifier to increase your bonus to hit by the number of points expended.

Whirlwind, 2 performance points

You spin on the spot and attack all enemies in a 5 foot range. All enemies within range make a Dexterity Saving Throw. On a success they take no damage. On a fail they take normal weapon damage from both weapons you're dual wielding.

Improved Critical

At level 7 your critical strike range increases by 1. You now critically strike on 19-20.

Hearty Presence

Level 10. You are usually the most physically intimidating presence on the field of battle. Your blade dance has pushed your body and improved it. When the fighting starts, most people look to see what you will do first. Add your constitution modifier to your initiative rolls.

Choreography

Level 15
Your training as a Blade Dancer has improved your ability to wield weapons with greater ease. You know the flow of each weapon and just how to use it. You can now use any one handed weapon (does not require light property) when activating The Dance Never Ends off hand attack with critical hits. All other rules for dual wielding, weapon proficiency, attack bonuses, and damage bonuses still apply.
Your attacks now count as magical for overcoming resistances and immunity. 

Heart of the Dancer

Level 18
You live for the dance. You know how to wield weapons more effectively than most while avoiding the blows of you enemies. Your training has pushed you to your peak.
Your Dexterity score increases by 2, and the maximum increases to 22.
Your critical strike range increases by another 1. You now critically strike on 18-20.