From Pathfinder Lost Omens The Mwangi Expanse, which isn't enabled.

Oath of the Devoted

ITEM 9

Usage held in 1 hand

Bulk —

You gain fire and mental resistance 5. When you die, you rise as an undead creature with the zombie trait on the next round; if you are a PC, you become an NPC under Walkena's control. Your stats remain the same, except that your alignment changes to evil. If you reach 0 Hit Points as a zombie, you are destroyed and do not rise again.

Activate command

Frequency once per day

Effect You gain a +1 status bonus to Will saves. Choose a weapon or an unarmed Strike; your chosen attack deals an extra 1d6 fire damage for the next 1 minute.

Effect: Oath of the Devoted

Special If you are a zombie at a time when Mzali is entirely purged of foreigners, your duty is fulfilled and you are immediately destroyed.

Pathfinder Lost Omens The Mwangi ExpanseOGL