Kohlebiss

There is a chimney that stretches to the very top of She of Steel, the short and squat member of the Sisters, trailing smoke into the sky all day and night. It starts much further down in the old magma chamber where it sits within Plinian's workshop.

At the base sits a snapper. To be precise, a fossil of a snapper. It is immense, dwarfing even the largest imperial, with the base of the chimney stack emerging from its back. As it turns out, fossilized snappers make incredible furnaces. Nobody knows who the ancient snapper was, nor how they ended up in the depths of the mountains within the land of Ice. Or how they became so incredibly large in the first place.

Plinian shovels coal into this snapper's body day in and day out, constantly forging all sorts of things like armor and glass. He, and many other members of the lair, leave offerings to the spirit of the snapper in thanks for the use of its body in death and to beg forgiveness for them not knowing who they were. So far, the fires have yet to ever die.