Nihilex

Nihilex refers to the overall species of a strange, corrosive, semi-sentient energy form that is invasive to Axxenith.

It is nothingness, emptiness, the great voidance within the world that does not destroy, but consumes, infests, and drives all existence to become null and void. The origins of Nihilex are unknown, and while there have been many theories, none know the factual genesis of the antithesis to life itself made physical. Nihilex is more than just a stagnant, nullifying energy found en masse, however; Nihilex has shown very specific traits of seeking to spread it's influence to living creatures so that it further inflicts itself on the world. Nihilex thrives and multiplies off of stagnation, broken will, and despair, and when directly influenced, living things lose the will to survive. However, depression, anxiety, and fear of becoming null creates a powerful reaction in living things; seeking some desperate means of survival, horrible, destructive tendencies develop in those afflicted, needing absolutely anything to escape the destruction of the self that the Nihilex represents.

Humans have shown a broad array of reactions to Nihilex; some show tendencies of suicide or homicide, some use the Nihilex as a tool to give them power, harming others while their minds are twisted by the energy. For some the influence of Nihilex is a much slower process, and this can be far more beneficial to the Nihilex -- If It can slowly poison the mind, it can force an individual toward manipulative tendencies, further spreading influence and creating a large crowd of "followers" who -- unknowingly or otherwise -- continue the infectious spread of Nihilex themselves.

The only antithesis to Nihilex is survival, creation, anything that prevents stagnation and promotes life itself; and so, a constant battle against the living and Nihilex began.

Forms
Nihilim - Formless, grouped spaces of Nihilex. A kind of energy more than a living creature, very tar-like in concentrated forms, easily converts to fog, smoke, or even a less thick liquid to mimic water. Not really sentient, but seems to operate like fungus in many ways, having a will to survive and use whatever it can as a host. Usually the most commonly found form of Nihilex, and often taken for granted on how dangerous it is; it does not take much Nihilim to infest a human, and in great enough quantities, the bodies of the afflicted may simply cease functionality.

Nihilus - a singular, living entity, "The Nihilus came to us in the body of a great animal..."

Nihili - plural living entities, "Many Nihili were invading the town."

Originally, Nihilim was thought of as quite difficult to destroy; Burning it, compacting it, storing it to keep it from spreading were all methods that ended up failing in one way or another, among many other ideas.

Origins of Nihili
A group of Unbound had an idea; Since the antithesis of Nihilex was life, then perhaps creating life from Nihilim would be a means of destroying it for good.

Indeed, initially it seemed to be a very productive idea; Several Unbound came together to change the state of Nihilex's matter into that of a living, breathing creature. This creature, however, had no instinct or will to survive; it simply wasted away, very quickly perishing. It seemed, though, that creating something from Nihilim had certainly reduced it's mass overall, so they tried again and again using the same material. The issue was, however, that organic life that humans know has the will to survive -- Eventually, after repeating death again and again, the Unbound working with the Nihilex-based creature noticed a change.

The creature had developed some sort of sentience. It no longer remained an unresponsive, quickly dying lump on the ground; instead, it's eyes regarded them, and it's sides heaved as if trying to understand while still feeling hopeless. Continuing their efforts proved to be a bad idea -- Soon enough, the creature had mutated into something that would try to outsmart it's captors, and operated on a destructive mind alone -- it had to destroy in order to survive, even if it meant risking itself in the process. However, of course, this reaction was flawed, and the creature was so reckless that it ended up destroying itself, but the result was clear; The Nihilim had found a means of survival. Feeding off the reaction of the creature and the anxieties from it's captors, the Nihilim could now reform the body without any outside interference, and after destroying the Unbound when they were off-guard, certain of the creature's death, it escaped to the outside world.

Since then, the beast, having fed on many other creatures and animals, split it's body again and again, each devoured life becoming a new monstrous entity, developing a mind to survive without instinct, broken and desperate from it's genesis. The Nihilus adapted and evolved to where they found shelter and easily perturbed life, and before long there was a new agent of Nihilex that would try to further overtake the world.