From Pathfinder Lost Omens Cheliax, Infernal Inheritance, which isn't enabled.

Unrelenting Terror

FEAT 5

Once you latch onto a foe's fear, you don't let go. A creature you successfully Demoralize becomes temporarily immune to your further attempts to Demoralize for only 1 round, instead of 10 minutes. If you fail to Demoralize, they are temporarily immune for 10 minutes as normal.

Pathfinder Lost Omens Cheliax, Infernal InheritanceORC