Shield Weapon Mastery

After weathering the barrage of barbed arrows, Cato’s detachment locked shields and prepared to endure the foetid charge of the undead horde. With a well-practised thrust, the veterans’ bulwark collided with the enemy’s rusted blades, sending foes reeling and weapons clattering to the floor. Equal parts fortification and battering ram, the outnumbered defenders deflected blow after blow against the attackers, turning the unholy horde on itself.

Shield Property.
A shield is typically made from wood or metal and is carried in one hand. Wielding a shield of any kind increases your AC.

Weapons With The Shield Property:
-Buckler Shield, Heater Shield, Tower Shield.

Tier 1 Advanced Techniques.

Shield Wall

Prerequisites: martial level 2, proficiency with Shields
While you are wielding a shield and within 5 feet of an allied creature that is also wielding a shield, your AC increases by 2. This effect does not stack.

Reinforcement

Prerequisites: martial level 2, proficiency with Shields
While you might not intercept every blow, you can cause minor deflections that decrease their efficacy. While you are wielding a shield, when you take damage from an attack, you can reduce the damage you take by an amount equal to your proficiency bonus (no action required). After you use Reinforcement, you can’t use this technique again until the start of your next turn.

Tier 2 Advanced Techniques.

Superior Strikes; Shields

Prerequisites: martial level 6, a tier 1 Shield advanced technique
You can perform a superior strike with any Shield.

Tier 3 Advanced Techniques.

Cover

Prerequisites: martial level 10, a tier 2 Shields advanced technique
While you are wielding a shield and within 5 feet of an allied creature who is not wielding a shield, you can use your bonus action to grant that creature a bonus to its AC equal to your shield's bonus until the start of your next turn. The bonus ends early if the creature is ever more than 5 feet away from you or you are incapacitated.

Numbing Collision

Prerequisites: martial level 10, a tier 2 Shields advanced technique
When a creature misses you with a melee attack while you are wielding a shield, you can use your reaction to strike its attacking limb, numbing it. The creature must succeed on a Constitution saving throw or drop the weapon that it used to make the attack (if any) at your feet. In addition, until the end of its next turn, it has disadvantage on attack rolls it makes, and it can’t pick up the weapon while you occupy the space and are not unconscious.

Tier 4 Advanced Techniques.

Bulwark

Prerequisites: martial level 14, a tier 3 Shields advanced technique
You are a wall capable of withstanding any onslaught. While you are wielding a shield, when you take damage from an attack, you can reduce the damage you take by an amount equal to your proficiency bonus (no action required). This effect stacks with Reinforcement, allowing you to reduce the damage you take from an attack by twice your proficiency bonus. After you use either Bulwark or Reinforcement, you can’t use either technique again until the start of your next turn.

Redirect Strike

Prerequisites: martial level 14, a tier 3 Shields advanced technique
When you are wielding a shield and you are targeted by a melee attack by an attacker you can see, but before the GM determines whether the attack roll succeeds or fails, you can use your reaction to add half your proficiency bonus to your AC against that strike, potentially turning a hit into a miss. If the attack misses, you can force the attacker to target a different target that is within 5 feet of both you and the attacking creature with the attack. Use the attacker’s original attack roll to determine if the attack hits.