From Pathfinder Lost Omens World Guide, which isn't enabled.

Necromantic Resistance

FEAT 4

Prerequisites Lastwall Sentry Dedication

As part of your training, you've inured yourself against necromancy through repeated exposure. You gain a +1 circumstance bonus to saves against necromancy effects and gain resistance to void damage equal to half your level.

Pathfinder Lost Omens World GuideOGL