Shield bearer

At 4th fighter level you gain the following benefits:

• Your shields provides you an additional +1 bonus to AC.

• You gain a +1 bonus to all strength and dexterity saves while wearing a shield, and all saves against ray and cone based attacks/effects.

• You gain +1 block at the start of combat.

• You can make a shield bash every time you block a melee attack as a free action.

• Gain two fighting skill tree upgrades from the armor training branch.

At 5th level, the damage dice of your shield bash attack is increased by 1 size category. 

At 5th level, you can choose a defense style ability from the list below:

• Shield taunt - You can spend an instance of block to slam a creature within melee range with your shield. It must make a dexterity save. The DC is strength based. Add any bonus your shield has to the DC. On a failure, the creature takes shield bash damage and has disadvantage on its next attack. You can do so twice on your turn.

• Iron mountain - While wearing heavy armor, you reduce all incoming weapon damage by your strength modifier.

• Vigor - Your second wind heals for 1d4 health per rest dice spent more.

• Disruptive - You gain advantage on all checks made to preoccupy, block, restrict, or obstruct enemies, or to cause them to attack you instead of an ally. Increase maximum health by 1d6.

At 6th level, roll 1d6 > 5 chance dice at the start of your turn if you are below half your maximum block (rounded down, min 1.) On a success, you regain 1 block. 

At 6th level, If you are wielding a shield, or are wearing medium or heavy armor, you gain advantage instead of disadvantage to checks made to block a critical hit.