Petra, Priestess of the Dead

The denizens of the wasteland speak of a powerful witch who dwells among the ruins.
She is called Petra, The Priestess of the dead.
It is said she has unlocked the secret ways of the Ancients, and can bring the dead back to life.
She does her unnatural works in a giant fortress called The Arkham Resurrectorium:


She is guarded by hundreds of followers, many of which she has created herself.
They are referred to as The Necromatons.