RWBY: WORLD OF REMNANT
Dust. By definition, it is a naturally occurring energy propellant that can be triggered by the Aura of Humans and Faunus. But in reality, it is much, much more.
Found in four basic forms, Dust can be combined both artificially and naturally to form new, stronger types, each with unique properties. Since its discovery, man has concocted a multitude of ways in which to harness these mysterious crystals.
From airships to androids, Dust has made its way into practically every facet of technology. Some prefer to use Dust in its raw form: elegant, yet destructive. Those who choose to wield Dust in this state must posses a certain level of discipline, to ensure that their resulting powers do not break free from their control.
Dust ammunition serves as a more practical application in today's modern society. With the technological advancements in weapon design, warriors need merely choose the right cartridge for the job and pull the trigger.
While this has become the standard method of use, it is not uncommon to find individuals still practicing more archaic forms of Dust manipulation, such as weaving it into clothing or even fusing it directly with their own bodies.
Despite working, fighting, and even turning a profit with it, humanity has still yet to understand how Dust came to be, and more importantly, how their involvement with Dust will ultimately change the world of Remnant.