Benefit: You must declare that you are using this feat before you make your attack roll (thus, a failed attack roll ruins the attempt). Draining Strike forces a foe that was damaged by your unarmed attack to attempt a Fortitude saving throw (DC = 10 + 1/2 your character level + your Wisdom modifier), in addition to dealing damage normally. A defender who fails this saving throw is fatigued for 1 minute or until the foe is subject to any spell or effect that heals hit point damage
any spell that deals hit point damage . If you have a base attack bonus of +14 or higher, the target is exhausted for the same duration instead. You can attempt to use Draining Strike once per day for every 4 character levels you have, but you can use it no more than once per round. Constructs, incorporeal creatures, plants, undead, and creatures that are immune to critical hits cannot be affected by this ability.
Pathfinder Roleplaying Game Advanced Class Guide © 2014, Paizo Inc.; Authors: Dennis Baker, Ross Byers, Jesse Benner, Savannah Broadway, Jason Bulmahn, Jim Groves, Tim Hitchcock, Tracy Hurley, Jonathan H. Keith, Will McCardell, Dale C. McCoy, Jr., Tom Phillips, Stephen Radney-MacFarland, Thomas M. Reid, Sean K Reynolds, Tork Shaw, Owen K.C. Stephens, and Russ Taylor.