at the 3rd level when you choose this archetype, you gain the ability to summon an arcane splinter. this splinter is an ethereal copy of yourself and is easily distinguished from you id you are present

you may spend a bonus action to summon your splinter and have it appear within 30ft of you in an unoccupied space you can see. on your turn, if you can see your splinter you can use your bonus action to have it move up to 25ft and use its action it also has its own reaction but it cannot use both its action and reaction in the same round. actions it can use are listed below

your splinter cannot take damage, but it is dispelled if you are knocked unconscious or is targeted by a dispel magic effect. if your splinter is dispelled you must make a DC 14 Wisdom check at the start of your turn to be able to summon it again

• attack: you may use your splinters action to a reaction to make a single melee attack to opportunity attack. is copies the weapon you are using its properties but does not do the same damage. all attacks made by a splinter deal twice your Wisdom modifier in force damage, the splinter uses your attack bonus on attack rolls 
• martyr: you may use your splinter's reaction, and reduce the damage of any attack or spell amount to 1d10+ your fighter level. If the damage reduced is less than the amount taken, the splinter remains but is moved adjacent to you. 

 

Back To Back

at 7th level, you have learned to fight alongside yourself and gain advantage on attacks made against creatures that your splinter is adjacent to. additionally, enemies have disadvantage to attack you if your splinter is adjacent to you as it intercepts and distracts. 

Skilled Splinter

at 10th level, your splinter has gained a greater, more stable sentience. This allows it to act more without your guidance. your splinter may now use both its action and reaction in a round it also gains additional options for its reaction and its attacks deal three times your wisdom modifier in force damage

• Riposte: if a creature misses you or an ally with a melee attack and your splinter is within melee range,, you may have it use its reaction to make an attack against that creature 
• intercept: if you are an ally of the target, you can use your twins reaction to move up to 15ft and give you or an ally +3 to AC

Self to Self

at 15th level, you may spend a bonus action to switch places with one of your splinters via a quick teleportation 

Triplets

at 18th level, your skill at using and summoning your splinter is so efficient that you now summon two splinters instead of one. when you use your bonus action to order a splinter they may both use an action 

Improved Critical

Beginning when you choose this archetype at 3rd level, your weapon attacks score a critical hit on a roll of 19 or 20.

Remarkable Athlete

Starting at 7th level, you can add half your proficiency bonus (round up) to any Strength, Dexterity, or Constitution check you make that doesn’t already use your proficiency bonus.

In addition, when you make a running long jump, the distance you can cover increases by a number of feet equal to your Strength modifier.

Superior Critical

Starting at 15th level, your weapon attacks score a critical hit on a roll of 18–20.

Survivor

At 18th level, you attain the pinnacle of resilience in battle. At the start of each of your turns, you regain hit points equal to 5 + your Constitution modifier if you have no more than half of your hit points left. You don’t gain this benefit if you have 0 hit points.