The Dark Ascent

It appears in the alternative timeline The Black Sun.

History
In the Ruined era, the fallen Osprix have founded a cult that worships the Void. Thrilled by their lust for destruction, the Osprix aid the alien creatures and prepare for a great plan.

The Traveler seeks for the cultist leaders in the cult encampment. They are however not found in the original headquarters, rather further up on the top of the cliff. Eventually the Oracle of the Black Sun and the Prophet of Dawn are located and confronted in a final battle, putting an end to their machinations.