Your fiendish power inspires primal fear in those you threaten.
Prerequisites
Intimidate 5 ranks, Planar Bloodline (Demon or Devil) or Fiendish Pact.
Benefit
You gain the Fear Aura special ability and may activate it once per encounter as a swift action. This aura remains in effect for a number of rounds equal to the number of fiendish feats you possess.
Any creature within 30 feet of you must make a Will save (DC 10 + your ranks in Intimidate + your Charisma modifier) or become shaken for the duration of this aura.
If a creature makes a successful save against your aura, they are immune to it for the duration, even if they leave the area and return to it. A shaken creature who leaves the range of your aura remains shaken, but it does not make a new save if it reenters the area of effect.