Guardian's deflection
Level 6
FighterTrigger: An ally within your melee reach is hit by an attack, you can see the attacker, and the ally gaining a +2 circumstance bonus to AC would turn the critical hit into a hit or the hit into a miss.
You use your weapon to deflect the attack against your ally, granting a +2 circumstance bonus to their Armor Class against the triggering attack. This turns the triggering critical hit into a hit, or the triggering hit into a miss.