Fortified Monument Feat 13

Tapping into the divine magic that keeps the erosion of centuries at bay allows you to harden your body. You can cast cairn form twice per day as a 6th-rank divine innate spell that can only target yourself. In addition to the normal effects of cairn form, whenever a creature damages you with an unarmed attack or non-reach melee weapon, the attacking creature takes 8 bludgeoning damage.