The Lux

Voidkruk is perhaps the most inhospitable location within Tjiramor. The only plant life is brought to the volcano by the fanatical Flame Worshippers. The same holds true for animal life, with the notable exception of the Lux.
Discovered by the Flame Worshippers when they established their temple on Voidkruk's shoulders, the Lux resemble a large slug. They range from 4" in length at birth to about 24" in length at adulthood. Adult Lux weigh about 5 lbs.
Infant Lux have a mottled blue appearance. This changes as they age. At about 2 months, the Lux begin to display luminescent properties. First, the lighter blue areas glow with a pale yellow light. As the Lux continue to age, the darker areas glow orange, with the darkest blue glowing red. An adult Lux resembles the shifting magma inside the volcano.
No one knows if the blue colorations remain. Once a Lux begins to emit light, it never stops. The glow from within the slug is impossible to see beyond.
When Lux die, their bodies combust so no one has been able to examine a Lux without its glow beyond infancy. For this same reason, no one has been able to discover what causes the luminescence.
Some Flame Worshippers theorize that the Lux absorb heat and light from Voidkruk. Others theorize that they are somehow able to pull the energy from beyond the Void, perhaps from the Well of Creation itself.
In any case, the Lux appear to absorb heat energy in some way and give off a cooling property. Without this property, it is questionable whether the first Flame Worshippers would have survived long enough to build their obsedian temple.
Flame Worshippers are known to carry at least one Lux on their person at all times. Most carry the Lux in pouches draped over their necks in order to cool their bodies. They claim an emotional telepathy with the Lux, while also viewing the Lux as gifts from the Light Bringer for his sturdiest worshippers.
The Lux seem to have a hive mind. They can be seen working in concert to staunch a lava flow. On rare occasions, they have left their homes on the slopes and their pouches on the Flame Worshippers to seek out a wounded Worshipper and offer cooling comfort.
When a Lux combusts, hundreds of high-pitched tones can be heard on the volcano. This is the only time a Lux makes sound. The resulting keening echoes in the air.