Jae Wolftail wrote:
Nonlethal damage is HP damage that can just doesn't kill the target therefore, power attack works for merciful weapons, normally nonlethal weapons, and blunt weapons effected by the bludgeoner feat, as does piranha strike for light weapons under the same circumstances.
When you take nonlethal damage, keep a running total of how much you’ve accumulated. Do not deduct the nonlethal damage number from your current hit points. It is not “real” damage. Instead, when your nonlethal damage equals your current hit points, you’re staggered (see below), and when it exceeds your current hit points, you fall unconscious.
This is what is said in CRB which tells that Nonlethal damage is not HP damage