You can make two extra attacks when you take the Attack action, for a total of three attacks.

You can use a Bonus Action to regain 1d10 plus your Fighter level Hit Points. You can use this feature four times, and you regain expended uses when you finish a Long Rest.

If you use Second Wind as a Bonus Action, you can move up to half your Speed without provoking Opportunity Attacks.

You adopt the Defense Fighting Style. While wearing armor, you gain a +1 bonus to Armor Class.

You master five weapons, chosen from weapons with which you are proficient. You can use the mastery properties of those weapons. Mastered weapons: Greatsword, Flail, Light Crossbow, Longsword, and Handaxe.

You can take one additional action on your turn. You can use this feature once per Short or Long Rest, and beginning at Fighter level 17, you can use it twice before a rest, but only once on the same turn.

When you fail an ability check, you can expend a use of Second Wind to roll 1d10 and add the number rolled to the check, potentially turning failure into success.

You score a Critical Hit on a roll of 19 or 20 on the d20 when making an attack roll with a weapon or Unarmed Strike.

You gain proficiency in two skills of your choice. You gain proficiency in Athletics and Intimidation from your Soldier background, and choose Acrobatics and Perception as your Fighter skill proficiencies.

You gain an additional Fighting Style feat. You choose Two-Weapon Fighting, allowing you to add your ability modifier to the extra attack granted by Light weapons.

When you use Indomitable, you can expend a use of Second Wind to use Tactical Shift as part of the same reaction.

When you attack with a weapon whose mastery property you can use, you can replace that property's normal effect with Push, Sap, or Slow, as appropriate to the weapon.

You can use Indomitable twice before a Long Rest.

When you make an attack roll with Advantage and both d20s would hit, the attack deals extra damage equal to the ability modifier used for the attack.

You score a Critical Hit on a roll of 18, 19, or 20 on the d20 when making an attack roll with a weapon or Unarmed Strike.

You receive Ability Score Improvements at levels 4, 6, 8, 12, 14, and 16. Kettan uses these improvements to reach his final ability scores and gain the Tough feat.

You can invoke your military rank and experience to exert influence over soldiers and recognize the military hierarchy, customs, and insignia of organized forces. Soldiers loyal to your former command may provide limited aid when it does not endanger their lives or duties.