The Nephandi are the dark nightmares of the enlightened. having sold their souls to dark powers wasn’t enough. their avatars have been reshaped in horrible pocket dimensions called Cauls to serve the purpose of Descent rather than Ascension. their goal is to rip reality to shreds until not even dust remains. only then will all be free of the prison they believe this world to be.
Nephandi who die are reborn with corrupt avatars that whisper the dark song of Descent from the moment they awaken. The enlightened see them as a cancer in reality that must be driven out and burned away. It is the one thing that the Technocrats and traditions have ever truly agreed upon. It is a shame that they have never agreed long enough to finish the job.