From Pathfinder Lost Omens Tian Xia Character Guide, which isn't enabled.

Adamantine Body

FEAT 8

Activity reaction

Trigger An attack or effect would deal damage to you.

With your strong will and even stronger body, you shrug off an otherwise devastating blow. You gain resistance equal to 2 + half your level against all damage from the triggering attack or effect.

Pathfinder Lost Omens Tian Xia Character GuideORC