You have dedicated your impressive skills to the service of Asmodeus.
Benefits: In addition to its normal use, you can spend one use of the Devil’s Pact whenever you make an attack against a foe that you flank, or that is flat-footed. If the attack hits, it deals damage as normal and the target is also staggered for one round. If the target is an outsider with the good subtype, it is instead staggered for 1d4+1 rounds. Creature’s that are staggered by this feat take a – 4 penalty on Perception and Sense Motive skill checks.
In addition, you can use the Devil’s Pact one additional time per day.
Way of the Wicked Book Five — The Devil My Only Master. Copyright 2012, Fire Mountain Games LLC; Author: Gary McBride.