You deliver unchecked destruction when you stand against multiple foes, sometimes to your own detriment.
Benefit(s): Whenever you use Cleave or Great Cleave, you can apply the additional damage you would gain from Vital Strike, Improved Vital Strike, or Greater Vital Strike to the initial target of your attack. When you do so, the strain on your body causes you to take an amount of damage equal to the extra damage dealt by your Vital Strike feat. This self-inflicted damage is not reduced by damage reduction.
Pathfinder Player Companion: The Harrow Handbook © 2014, Paizo Inc.; Authors: Crystal Frasier, Will McCardell, and David Schwartz.