Needs review
Source: Way of the Open Hand

Description: You learn how Witch-Hunters have protected themselves

Prerequisites: WIS 13, Improved Unarmed Strike, Void Use

Required for: Sagasu-do Advanced, Sagasu-do Master

As a full attack action, you may gain a +2 damage bonus on a single unarmed attack. If your target has the Shadowlands subtype, and you are aware of this fact beyond a shadow of a doubt, you may spend a Void Point to increase this damage by your Wisdom Modifier. (If the target turns out not to be Tainted, the Void Point is still spent. Thus, if there is the possibility the target was not Tainted there is no true way for you to be sure by using this feat.)