Coolers
The Coolers keep the Forge Deep from destroying itself. Heat does not leave anything in the Deep once it is there, and it builds; the Coolers release it at the right pace, so that it does not burst out all at once in an eruption that would end the zone and everything in it.
Appearance
A Cooler looks like a drift of dark smoke shot with dull red, the size of a large dog, that moves along the magma rivers and the cracks of the cavern floor. Where it passes, the glow of the stone dims a shade and a thin steam rises. In the Deep’s slowed time it seems to drift very slowly, and it makes a long, soft exhalation, like a bellows drawn back, that goes on for minutes. The air near one is a little less heavy, and smells of wet ash.
Habitat and Range
They move along the vents, cracks, and magma rivers, gathering where heat builds most. A Deep holds a number of them, never many, and they are found nowhere else.
Behaviour and Temperament
Coolers show no interest in visitors and no mind that anyone has been able to reach. They go to where the heat is building and draw it off slowly, through vents and cracks, so that the Deep never boils over. They work with the Smiths without speaking to them, and the Smiths move their forges aside for them.
Abilities
They draw heat from stone, magma, and air and let it out by slow paths. What they cannot do is hurry: a Cooler forced to take too much at once seems to break apart.
Uses and Dangers
The Deep’s existence depends on them, and with it every alloy and artefact made there. Anyone who traps, drives off, or kills a Cooler risks the eruption they hold back.
Lore and Belief
Smiths of the world above call the Coolers the Deep’s breath, and say a forge that goes too hot needs one. Some of the Smiths of the Deep say the Coolers were made by the first of their kind; others say the Coolers made the Deep habitable before any Smith came.