A great complex of caverns made of purple-brown stone in high, arching formations, and lit by lanterns, light spells, or absent both of those, a deep orange ambient glow that comes from deep slits in the walls that offer a small peek into glowing lava flows beyond.
Possibly the most user-friendly of the complex’s chambers, the Main Cavern is well-lit, well-populated and furnished for all creatures great and small. Its name is a little deceptive, as well: The Main Cavern itself is the main chamber of this section of the Firecaverns, but it has many branch-offs, including an ever-growing resident section to the east and a great number of ‘environment’ caverns to the west. These latter terminate in the Firecavern Cattery and Lofts, and it is extremely common for Hunter Cats or winged pigeon-cats to be found lounging in the Main Cavern along with the more sapient residents.
The residential rooms, though more hospitable and house-like than most of the caves in the complex, still have the aspect of being underground. With the exception of some of the environment caves, rocky ceilings and walls are openly visible or obscured only by wall-hangings and lights, and the ground underfoot feels to the touch like polished concrete but is striated and coloured like the rest of the Caverns’ walls.
Outside the radius of the inhabited caverns and the environmental caverns, the connected spaces get rougher, more naturalistic. On the same level of of elevation as the Main Caverns themselves, going far enough out will take an explorer into dangerous spaces: caves tight and windy enough to get stuck in, or great broad open spaces lit luridly by flowing lava that throws up fumes and flames.
The main room has a floating, glowing orange directory in it for visitors to the complex, including a map of the caverns that terminates at the entrance to the Undercaves as well as a more specific diagram of the Main Cavern and connected caves.