Dwarven Seething (Combat)Source Weapon Master's Handbook pg. 12
Your hatred drives every swing of your weapon.
Prerequisites: Dwarven Hatred Style, base attack bonus +5, defensive training and hatred racial traits, Medium size.
Benefit: While using Dwarven Hatred Style, when an opponent hits you with an attack (including a spell that requires an attack roll), you can apply your defensive training or your hatred racial trait bonus (your choice) against that target, regardless of the opponent’s type or subtype, as an immediate action. This ability lasts until the opponent dies, the combat ends, you change styles, or you designate a different opponent with this ability, whichever occurs first.