Source: Oriental Adventures
You can bellow forth a ki-empowered shout that strikes terror into your enemies.
Prerequisite: Base attack bonus +1 or higher, Cha 13+
Benefit: Making a ki shout is a standard action. Opponents who can hear your shout and who are within 30 feet of you may become shaken for 1d6 rounds. The ki shout affects only opponents with fewer Hit Dice or levels than you have. An affected opponent can resist the effects with a successful Will save against a DC of 10 + 1/2 your character level + your Charisma modifier. You can use Ki Shout once per day.
Shaken characters suffer a -2 morale penalty on attack rolls, saves, and checks.