Agent of FearSource Ultimate Intrigue pg. 75
You inspire fear so powerful that it’s hard to shake off.
Prerequisites: Persuasive, frightening appearance class feature.
Benefit: When you target a creature with your frightening appearance or stunning appearance class feature, it does not become immune to the effects of those features for 24 hours, but does gain a +2 bonus on the saving throws against those class features for 24 hours. This bonus stacks with itself if you use those abilities against the same creature multiple times in the same 24- hour period. Because these abilities alert the creature to your presence, you still can’t use them on the creature again until after the end of that specific combat.
Normal: A creature targeted by frightening appearance or stunning appearance becomes immune to the feature’s effect for 24 hours.