Twin Shield

As a warrior who has forsaken traditional weapon, you may have sworn never to take a life with a weapon again, or have taken a vow to protect rather than to draw blood, you have picked up not one but two mighty shields. Every warrior knows shields are used primarily in defense, however this has become a tactic of illusion for you. As someone who has seen, and begun to master the ways of the Twin Shield, you have realized the truth when wielding two shields:

Defense, is a good offense.

Shield Bash

When you choose this martial archetype at 3rd level, the offensive power of shields becomes apparent to you. Your shields are now considered melee weapons for you, which you are proficient with. These weapons deal 1d6 Bludgeoning damage and add your Strength modifier to their attack and damage rolls.

If the shield you are using is magical, melee weapon attacks with it count as magical for the purpose of overcoming resistance and immunity to nonmagical attacks and damage. The magical bonus a shield could apply only effects it's AC bonus, not the bonus of any of its attack or damage.

Protective Stance

As someone wielding two shields and clad in armor, you have learned to care for both beyond the normal rigors of day to day use and use them as though they were an extension of your very hands. At 3rd level, you can enter a Protective Stance as a bonus action on your turn.

While in a Protective Stance, you gain the following benefits while you are wielding two shields and are not incapacitated.

• You and allies within 5 ft of you gain a bonus 1 to their Armor Class. This bonus increases when you reach certain levels in this class, increasing to 2 at 7th Level, 3 at 10th Level, 4 at 15th Level, and 5 at 18th Level. 
• Whenever an ally within 5 ft of you is the target of a ranged attack you can see, you can choose to become the target of the attack instead.
• Whenever you grant an ally of yours cover, you grant that ally three-quarters cover instead of half-cover as long as that ally is not large or larger.
• Opportunity attacks against you or an ally within 5 ft of you have disadvantage.

You can keep up this Protective Stance for 1 minute. It ends early if you are incapacitated, if you stop wielding two shields, or you are no longer wearing heavy armor. You can also exit your Protective Stance at any time you choose (no action required).

You can use this feature two times. You regain all uses of this feature once you complete a short rest.

In addition, due to the care that you must take in repairing  your shields and armor so that they can provide you peek protection, you gain proficiency with Smith's Tools if you don't already have it.

Interposition

At 7th level, you have begun to throw caution to the wind and defend your allies with increasing vigor. While you are in your Protective Stance and an ally within 30 ft of you would be subjected to an attack, you may use your reaction in order to move to within 5 ft of that ally.

You can use this feature up to a number of times equal to your Constitution Modifier (minimum of 1). You regain all uses of this feature after you complete a short rest.

Meteoric Armaments

At 15th level, you have learned to use your shields in a masterful form of offense, crashing into targets with their shear weight. If you move at least 20 feet straight toward a creature and then hit it with a melee weapon attack from one of your shields on the same turn, that target must succeed on a Strength saving throw or be knocked prone. If the target is knocked prone, you can make one additional melee weapon attack with one of your shields against it using a bonus action. You can use this feature no more than once per turn.

The saving throw DC for this attack equals 8 + your Strength modifier + your proficiency bonus.

Weight Behind It

At 15th level you have learned how to use shields as absolutely devastating weapons. Whenever you deal damage with one of your shields, you gain a bonus to its damage rolls equal to your Constitution Modifier.

Adamantine Will

Upon reaching 18th level, armor and shields which reinforce you and your allies is ever present and while you’re in your Defensive Stance, any critical hit against you or a creature within 5 ft of you becomes a normal hit.

In addition, when you are subjected to a magical effect that allows you to make a Strength or Constitution saving throw to take only half damage, you instead take no damage if you succeed on the saving throw.