A Stalker Vigilante can take an ability which deals hidden strike damage as non-lethal fear damage if they succeed on an intimidate check and make the opponent(s) shaken.
Does DR/- or DR/x apply to this? It is not direct weapon damage. And DR applies to direct weapon attacks.
Here's the skinny on what's happening:
Dazzling Display: While wielding the weapon in which you have Weapon Focus, you can perform a bewildering show of prowess as a full-round action. Make an Intimidate check to demoralize all foes within 30 feet who can see your display.
Intimidate: Demoralize - You can use this skill to cause an opponent to become shaken for a number of rounds. This shaken condition doesn’t stack with other shaken conditions to make an affected creature frightened. The DC of this check is equal to 10 + the target’s Hit Dice + the target’s Wisdom modifier.
Success: If you are successful, the target is shaken for one round. This duration increases by 1 round for every 5 by which you beat the DC. You can only threaten an opponent this way if it is within 30 feet and can clearly see and hear you. Using demoralize on the same creature only extends the duration; it does not create a stronger fear condition.
Fail: The opponent is not shaken.
Twisting Fear (Ex): Whenever the vigilante causes an opponent to gain the shaken, frightened, or panicked condition, that opponent takes an amount of nonlethal damage equal to the vigilante’s reduced hidden strike damage, as the stress wears upon its body. A creature can’t take damage from twisting fear more than once per round. Panicked creatures that take damage from twisting fear are too winded even to scream as they flee in terror. Only a stalker vigilante can select this talent.
So, does DR apply? You are not actually striking them, it is a mind-affecting effect (not a body one). So I wouldn't think so, even if the damage is "equal to" some damage their weapon does. And point of fact, you don't do weapon damage (thus wouldn't bypass DR/S,P,B, even if this was applied due to wielding a S,P,B weapon), just hidden strike damage. Thoughts?
(ps. the more I think about it the more absurd I think it would be to apply DR to a mind-affecting effect... like does it work against illusions? No. Then why would it work against this? Of course, the whole ability to damage people with intimidate and not hitting an AC is pretty absurd too, but also adding to not being weapon damage and subject to DR that way as well... sigh... )
An 'Attack' is not an offensive action resulting in an opponent's harm.
An 'Attack' is an action with an Attack Roll.
You don't apply Sneak Attack damage to a Fireball or Lightning Bolt, because they're not Attacks. Even though both spells have the capacity to annihilate the population of a small town, they're not mechanically considered Attacks.
So you can definitely hurt opponents without using Attacks.