The Legionnaire is a veteran of the battlefield that maneuvers with deadly efficiency from one encounter to the next. They aren't focused on the fight at hand, but getting to the next one. They do this be by engaging with efficiency, grace, and ruthless proficiency.

Level 15: Battle Efficiency

Your experience in battle has taught you new ways to be more effective on the battlefield. As such you are able to use your EP in the following methods:

Dexterous Movement - If you are targeted by an action that requires you to make a DEX Saving Throw as part of its effect, that you can see, you may use an EP as a reaction. When you do so, add a DP Die to your saving throw. If you make the save, and the result would see you take half as much damage as a Failure, you instead take none. After the action is resolved, and part of the same reaction, you may make a weapon attack against a creature within range (Melee or Ranged). 

Deft Deflection - If you are the target for a ranged weapon attack by a creature that you can see, you may use an EP as a reaction before you know the result of the attack roll. If the attack is successful, roll your EP Die and add your INT Modifier. If your roll is higher than the damage roll, you deflect the projectile back toward the attacker, and they take difference between their damage roll, and your EP Die + INT Modifier as damage of the weapons type. Afterward, and part of the same reaction, you may make a weapon attack against a creature within range (Melee or Ranged)   

Harm's Way - If an allied creature within 5ft of you is targeted by a melee attack, you may use an EP as a reaction to make you the target instead. If the attack is successful, roll an EP Die, and subtract the resulting roll from the damage you would have taken. If the damage is reduced to 0 as a result, the attacker is stunned. After the attack, and part of the same reaction, you may make a weapon attack against a creature within range (Melee or Ranged).

Level 18: Combat Surge

You gain an additional use of Action Surge. 

When you action surge, you gain the effects of the spell, Haste This effect lasts for rounds, and does not require concentration. During this period, the roll that you need to make a Critical Hit becomes 19-20.

In addition, you can spend five EP in order to recharge a single use of Action Surge. This can be done up to as many times as your proficiency bonus. When you use your EP in this way, you may choose to have Action Surge take effect immediately, or save it to use whenever you would wish. 

Level 3: Unhindered

While the Legionnaire remains proficient with all arms and armor, they prefer to move across the battlefield unhindered by the burdens of cumbersome armor. While not wearing MEDIUM or HEAVY armor, the Legionnaire receives the following benefits: 

Intelligent Defense - The Legionnaire adds their INT modifier to their Armor Class.

Deft Movement - The Legionnaire increases their walking speed by +5ft (This Increases to +10 at level 10). Additionally, after calculating the damage from a successful attack on a creature that the Legionnaire had targeted, they may move using any remaining movement speed, without taking an attack of opportunity that would have triggered from the effects of leaving a creatures attack range, or reactions from entering another creatures attack range. 

Level 7: Combat Prowess

When you make a weapon attack with which you use STR as your modifier, you may choose to use INT instead. Additionally, your combat prowess has taught you how to make the most out of every attack, allowing you to add your attack modifier to attacks made with an off-hand weapon. 

Level 10: Broad Strikes

If you make an attack against a creature using a melee weapon, you may choose an additional creature that is within 5ft of your target - and whom is still within your range - and target them as well, using the same attack roll. You can do this as many times up to your proficiency bonus + your INT modifier. 

Level 3: Efficient Blows

When the Legionnaire successfully rolls damage after making a melee attack, they receive an EP (Efficiency Point). They can stack up to five of these at a time, which they lose all of, if they make an attack for which no damage is rolled*, or if no melee weapon attack is made during a round**. When this fighter makes a successful attack roll, they may choose to use any number of these points, to add extra damage dice to their roll. The number of dice is equal to 1d4 per EP. 

This die increases at the following levels: d6 at level 7, d10 at level 10, and d12 at level 15.

*Special attacks such as but not limited to Shove, Push, or Grapple, are not able to grant an EP.
** In addition losing your EP points if a rolled melee weapon attack fails, you will lose your stack if you don't make a rolled melee weapon attack during a round of combat. By this end, attacks made with a reaction such as an attack of opportunity, or polearm master, are acceptable.