Defensive Fighting

Flexible melee attack
Trigger: 
Natural 16+; if you fight with a shield, also any natural even roll
Effect: 

Gain a +2 bonus to AC until the end of your next turn.

Adventurer Feat: 

You also gain the bonus to Physical Defense.

Champion Feat: 

The bonus increases to +3.

Epic Feat: 

You also gain the bonus to Mental Defense.