Line infantry

Here to hold the line and fight foes in a more traditional style. Using armor and towershields to wear foes down or fighting with ranged weapons to rain devastation from afar, he will bring destruction to the battlefield.

Hold Steadfast

Beginning when you choose this archetype at 3rd level, you are immune to being knocked prone or being frightened.

Infantry training

Starting at 7th, level you can choose your training. Infantry training influences your skills as a soldier.

Iron Wall

While you are wearing armor, you gain a +1 bonus to AC and -5 ft movement.

Skirmish

You gain proficiency with firearms and receive no long range disadvantage on ranged weapons, no reload on ranged weapons and +5 ft movement.

War drums

You gain proficiency in the use of Drums, proficiency & expertise in Athletics and +10 ft movement.

Battlefield tactics

At 10th level you can choose your tactics.

Charge

Rampaging throught the enemy lines, charge to break their formation. 
Charge into the enemy knocking them prone on hit, dealing 1d4 + CON.
Moving in a straight line for the distance of your total movement or until three enemies are knocked down.

Forced march

In order to gain tactical and strategic advantage, commanders could decide to do a forced march.
Disadvantage on opportunity attacks against you and you gain +50 ft movement.

Warcry

You yell so loud that the enemy gets frightened.
Each creature within a cone must make a Wisdom saving throw.
A creature is Frightened and knocked prone on a failed save, but if it succeeds the save it is only frightened.

Ruthless efficiency

At 15th level, you become a veteran of war, you can choose to get a permanent damage boost for melee weapons that adds an extra 2+STR damage or for ranged weapons that adds an extra 2+DEX damage.

Melee veteran

You can add an extra 2+STR damage to your melee weapon attack.

Ranged veteran

You can add an extra 2+DEX damage to your ranged weapon attack.

War veteran

At 18th level, you gain a +5 modifier on death saving throws and you also heal 1d4 on a succeeded death saving throw.