Miasmatic caldera

Seems like long before the Awakening, parts of some layers in The Depths collapsed due to the volcanic activity on the layers below them, creating a caldera. The gases released during the event filled the caldera, making an inhospitable, poisonous area.
But life finds a way in The Pit and so it did once again. Plants, fungi, and creatures capable of surviving in those terrains started showing up. And later, even some crazy people decided to "tame" the area.
The variety of species capable of surviving in areas filled with poisonous gases and the air with low contents of oxygen is truly intriguing. Intriguing enough that some of the researchers decided to find representatives of the tribes living in the caldera so they might hire them as guides while they gather their samples.

The gas

One can easily see the caldera long before they approach it thanks to the yellow-ish glow that can be seen from quite a distance. The gas filling it is dense, keeping close to the ground. It is a mixture of volcanic gases and secretions of living beings of the caldera. Once in a while, enough of it gathers up and spills out, either through cracks in the walls or by simply going over them. In both cases, a wave of hard-to-see miasma starts to move in the dark caves of The Depths.

Related Ethnicities

• Gasfield tribe

Taming the miasma

Among the four types of tribes of People of the Depths, there's one crazy enough to try to tame the caldera. The terraforming tribes often move to dangerous areas where almost no creatures live and either change the area to suit them or create protection from its hazardous properties.
Since the gases of the caldera are very dense, there are some tribes that decided to create their settlements on stilts to completely avoid it. The ones heavily inclined into technology either use specialistic air filters in areas that would be easily defensible, or use Air Crystals to do the same job