Spartan

The Spartan is one who has pushed their body to the limits of physical achievement and tempered it with superior tactics and defensive skills. As skilled with the shield as they are with their weapons, Spartans are pillars of strength that can be the difference between a party standing or falling.

Hardened Shield

Beginning when you choose this archetype at 3rd level, you gain an additional +2 AC when wielding a shield.

If you take the Attack action on your turn, you can use a bonus action to make a melee attack with your shield. If you do, you do not gain an AC bonus from equipping your shield and cannot do anything that requires having a shield equipped until the beginning of your next turn. You are proficient with it, and you add your Strength modifier to its attack and damage rolls. On a hit, you deal 1d4 bludgeoning damage and the target has disadvantage on maintaining concentration and cannot use its reaction until the end of its next turn.

Starting at 10th level, it also cannot take bonus actions until the end of its next turn. The attack also deals 1d6 damage. Starting at 15th level, it deals 1d8 damage, and at 18th level it deals 1d10.

Phalanx

Starting at 7th level, you can plant your shield and invoke a powerful barrier around yourself and your allies. As a reaction, you can move up to 5 feet and then use your shield to create a blue barrier around you and any number of creatures you choose within 5 feet of you. Any creature you choose that is wielding a shield can use its reaction to extend the area and include any number of creatures it chooses within 5 feet of it. All other creatures in that area must make a Strength saving throw, where the DC is equal to 8 + your Strength Modifier + your Proficiency bonus. Any creature that fails is pushed back 5 feet, outside the barrier. All creatures still within the barrier gain resistance to bludgeoning, piercing, slashing, fire, cold and thunder damage from sources outside the barrier and all ranged attacks from outside the barrier have disadvantage against them until the beginning of your next turn. Any creature trying to enter the barrier during that time makes a Strength check with disadvantage contested by your Strength check. On a failure, they are pushed back 5 feet instead.

Starting at 15th level, all distances are increased to 10 feet, and creatures inside the barrier also gain resistance to acid, thunder, radiant and necrotic damage from sources outside the barrier. Starting at 18th level, all distances are increased to 15 feet, and creatures inside the barrier gain advantage on all saving throws against sources outside the barrier.

You can use this feature once until you finish a short or long rest.

Guardian

At 10th level, you can use your action to protect others by taking on all attacks in their place. Each hostile creature within 30 feet of you makes a Wisdom saving throw, where the DC is equal to 8 + your Strength modifier + your proficiency bonus. For the next 1 minute or until your concentration ends (as if you were concentrating on a spell), you have a +3 bonus to AC and each creature that failed the saving throw has disadvantage on all attacks against creature other than you. You can use this feature once until you finish a short or long rest.

Centurion

Starting at 15th level, you can use your reaction to completely protect one creature from all damage. Until the beginning of your next turn, you or one creature of your choice within 30 feet gains immunity to all damage types. You can use this feature once before you finish a short or long rest.

Aegis Boon

At 18th level, you greatly enhance your shield techniques, gaining both strength and defense. When you use Phalanx, you gain advantage on all attacks you make until the end of your next turn. When you use Guardian, for the duration you gain resistance to all damage types as long as you are wielding a shield.