From Pathfinder War of Immortals, which isn't enabled.

Exemplar Resiliency

FEAT 4

Prerequisites Exemplar Dedication; class granting no more Hit Points per level than 8 + your Constitution modifier

You gain 3 additional Hit Points for each exemplar archetype class feat you have. As you continue selecting exemplar archetype class feats, you continue to gain additional Hit Points in this way.

Pathfinder War of ImmortalsORC