A shieldsman focuses on mastering the use of his shield in battle for both defense and offense.
Combat Focus I
At 3rd level, you gain Shield Focus as a bonus feat. If you already have this feat, you increase by the AC bonus of any shield you wield by an additional +1.
You also gain a +1 bonus on attack and damage rolls when making a shield bash attack.
Combat Focus II
Beginning at 5th level, you can use an immediate action to defend an adjacent ally, granting that ally your shield bonus to AC, including any bonuses granted by your combat focus. If the attack still hits defended the ally, you and the ally each take half damage from the attack, rounded up.
Combat Focus III
At 9th level, you gain Opportunist as a bonus feat, even if you don’t meet the prerequisites. In addition, as an immediate action, you can move up to half your speed before attempting to defend an ally when using your Combat Focus II ability.
Combat Focus IV
At 13th level, the shield bonus to AC, maximum Dex bonus, and armor check penalty of any shield you wield each improve by 1. The bonus on shield bash attack and damage rolls increases to +2.
Combat Focus V
At 17th level, the shield bonus to AC, maximum Dex bonus, and armor check penalty of any shield you wield again improve by 1, and the bonus on shield bash attack and damage rolls increases to +3.
In addition, you can move up to your full speed when moving to defend an ally using your Combat Focus II ability.