The high energy magic facility has recently been plundered (in the last few years.) It was a facility where anti-magion accelerator technology was explored.

Fireberg is the principle settlement. Pyromania is endemic due to a founder effect.

The volcano has been awakened by the magic of the cultists. They use it to get water from hydrated minerals. "Burning things is the path to happiness."

Chambers carved into the volcano. No one who is not heatproofed could survive long in there, the air temp is about 200C and one could survive it unprotected for only minutes. The ground is at least as hot.

The high priest of the cultists, Flashfire, Patriarch of Equus, will see the arrival of the party ("I saw your coming in the embers.") The patriarch wears an eyepatch, which conceals the fact that one of his eyes has been replaced with an obsidian stone that glows (The Eye of the Matriarch) and provides enhanced magical vision.

Flashfire knows about the "Great Evil." "An ancient enemy to the gods of our spiritual ancestors, the Shadhavar of the Dread Dimensions." "Perhaps our knowledge of the topic has been overstated, but I will have someone look into it, if you like."

FF and their religion blames the changelings for En-Netsusep. "The chastisement of En-Netsusep was necessary to save us, and the wider multiverse, from domination by the changelings. Their proliferation threatened independent sentient life, and their mode of operation is morally repugnant. It is unfortunate that En-Netsusep was not allowed to complete the work of extirpation. If he had, perhaps Equus would not be in such a poor state now."

Flashfire can read and speak shadhavar, but also knows of the magic puzzle specifically. "If it is to be unlocked, you must be prepared to defend it." "Let us see if you are."