From Pathfinder Lost Omens Knights of Lastwall, which isn't enabled.

Keep up the Good Fight

FEAT 14

Prerequisites Knight Vigilant Dedication

Frequency once per hour

Trigger A foe's Strike reduces you to 0 Hit Points.

Requirements You had more than 1 Hit Point before the triggering Strike, and the Strike wouldn't kill you.

Your devotion to helping others and doing good keeps you going, even against insurmountable odds. Instead of being knocked out, you are reduced to 1 Hit Point, gain a number of temporary Hit Points equal to your level for 1 round, and increase your wounded value by 1.

Pathfinder Lost Omens Knights of LastwallOGL