Kuuhruul

Kuuhruul appears as a black, viscious sludge when pulled from the ground. When the light hits the surface right, it can have a rainbow colored gleam running through it. As it is refined, the kuuhruul becomes thinner with less impurities.

The most notable property of kuuhruul is its flammability. Unrefined, it can light in a steady fire, but its flammability increases when refined to the point where it can be used in machines with controlled combustion to power the war engines of the goblins.

Kuuhruul comes from deposits in the ground, although no scholar knows how to predict where the deposits will be. They have to be found through trial and error.

Goblins had always had difficulty with magic, as there are no elves over the mountain to discover how to create esoterica, so goblins remained relatively behind culturally compared to the cultures east of the Wall. However, several decades ago, goblins discovered how to refine kuuhruul into a fuel source improving the efficiency of simple machines. Over the years, the goblins have slowly integrated kuuhruul into almost every aspect of their lives, especially their ramshackle war machines that have led to them forming an empire west of the wall. Now, kuuhruul is a cultural symbol associated completely with goblins despite it showing up all over the continent.

Kuuhruul is used to power various machines, primarily war machines, large siege engines and other kinds of weapons like ballistae. These war machines are self-propelled by kuuhruul, with the force of the weapons boosted even more by kuuhruul. Kuuhruul has also been used to power construction machines that allow goblins to build bigger and sturdier buildings. Some inventors are even working on prototypes for horseless carriages powered by kuuhruul engines.

Kuuhruul is one of two major materials that represent goblin dominance in the east. Along with degaar, a fine, black, exploding powder, kuuhruul is a symbol of goblins, and is recognizable to anyone west of the Wall as such.

Raw kuuhruul cannot be used as a fuel source due to being too heavy. Instead, goblins have found a way to refine it into a more usable form. They superheat the kuuhruul to separate into multiple components. From there, they identify the most potent and lightest of the components using their innate gift to see the energy potential in anything and then blend the chosen components back together into refined kuuhruul.

The most obvious danger of kuuhruul is its flammability. However, goblin kineticists have started warning that intense exposure to kuuhruul, especially during refinement, can cause respiratory issues and skin problems, although they've been ignored by goblin leaders.

For now, the only known impact of kuuhruul on the environment is that it contaminates water that it found or refined near, making it dangerous to drink.