Source: Dance of the Damned, pg(s). 71
Voiporl is the infernal realm of the whore queen Mahathallah, located in the caverns between Phlegethon and Stygia. It is contained entirely within vast caves, whose ceilings are in certain locations rent open to reveal dizzying alien constellations. The floors of the caverns are filled by a violet desert, dotted with ancient temples and oasis gardens the size of jungles.
In addition to Mahathallah herself, Voiporl is home to giant serpents and dragonflies, as well as witches, medusas, and undead, all of whom eagerly prey on the damned souls who come to the desert caves after escaping from the forges of Phlegethon.