From Pathfinder Lost Omens Divine Mysteries, which isn't enabled.

Mystic Aegis

REACTION

Activity reaction

Trigger A creature you have successfully Recalled Knowledge about would damage you

Requirements You have a free hand

Effect You brandish your charm, channeling and shaping the forces within it to protect you against harm. You gain resistance to all damage equal to 2 + half your level rounded up against the triggering effect.

Pathfinder Lost Omens Divine MysteriesORC