Strong Guard

Flexible melee attack
Special: 

You must be using a shield.

Trigger: 
Any miss
Effect: 

One ally next to you (including an ally engaged with the same enemy as you) gains a +2 AC bonus until the start of your next turn or until you are no longer next to them.

Champion Feat: 

Bonus also applies to PD.

Epic Feat: 

Bonus increases to +3.