The Impurities

The Impurities, as their name implies, are the impure elements of nature's core in the world of Dota 2.

Description
The evil Impurities are the impure elements that make up the hinterland at the innermost part of all nature, akin to how our nature is composed of the elements. Despite the Impurities being, well, impure, they can be "distilled to their essence" for some reason, contradicting their inherent impurity. Leshrac only mentions the said purification of his Impurities once he has been reincarnated, but it's not yet known what this distillation has to do with his reformation process.

The reality of all nature, according to the nihilosopher Leshrac, is all about torment and decay. As the elements of the core of nature, the Impurities embody all of these evil truths of the cosmos, such as torment and suffering; as well as pollution and corrosion. These Impurities embody chaos and hence they are the stuff of disorder in nature.

According to Leshrac, our form generally comes from the heart of all nature, which might explain the names of said realm. As the elements of the world that is the body's genesis, the Impurities may have a contribution to the creation of a being's body. This may explain why Leshrac knows the truth that all of nature is undergoing an existence of torment that they have yet to realize until they see the foul truth of reality for themselves. If the Impurities had a hand in providing our very forms, then we all may have traces of their influence, which is why all of nature turns out to be tormented like Leshrac all along...

Upon reviving, Leshrac mentions witless elements that restore his life, which possibly refers to the Impurities. It is unknown why they are witless, but it is known that they wield healing properties (which can be tapped into via ) and the ability to resurrect him. Apparently, the life that these Impurities give to him is unnatural.

List of Impurities
Like the elements that make up all nature, the Impurities are the elements that form reality's foul foundation. With these evil, blasted, tormented, and corrupted elements, the horrible hinterland that the Impurities constitute mirrors all of its elements' properties. The following are the four Impurities: All four Impurities are akin to the elements of air, water, fire, and earth, respectively; and they all seem to correspond with the four states of matter: solid, liquid, gas, and plasma.
 * Evil winds that apparently rise in upward currents from unknown origins. Perhaps they are destructive, hence the core of nature is blasted.
 * There's a windlike background sound in Leshrac's spell. Mayhaps this is what fluxes the Edict's Chronoptic energy between the planes. Who knows?
 * Tainted waters that can strengthen and sustain the consumer, although perhaps this only applies to those of the heart of nature.
 * When Leshrac drank these waters, he gained a growth of power-channeling branches and unnatural fungi that acts as armor with its stone-hard composition.
 * Apparently, the growths that come from these tainted waters, such as Leshrac's curved rack, can corrupt the soul beyond restoration if they are merely touched.
 * Sinister energies that apparently energize the likes of Leshrac, since he sounds quite pleased and refreshed upon receiving them.
 * It's possible that this sinister energy is actually Chronoptic energy, which also means that the latter is one of the Impurities.
 * Supporting this is Leshrac's spell. Its blasting energy flows from one plane to another, the former possibly being nature's core where the Impurities are.
 * Furthermore, is said to be an impure impulse. Its energy is implied to be Chronoptic energy as well, further implying its nature as an impurity.
 * Pulse Nova is implied to use Chronoptic energy because it has the same purple and orange color and same target SFX as the Chronoptic energy of Diabolic Edict.
 * With its apparent nourishing properties, this sinister energy might be the same as Chronoptic energy, since the latter also nourishes its respective crystals.
 * The Chronoptic energy of spreads the same torment that afflicts Leshrac.  As such, this Impurity embodies torment, one of nature's evil truths.
 * The brittle earth. Nothing else is known about it, besides it being brittle compared to typical earth possibly due to it embodying decay, one of the evil truths of nature.
 * Said element may be why he has the spell, since he destroys the earth in nature to make it mirror its brittle counterpart at nature's core.

Heroes
So far, is the only Hero (let alone character) in Dota 2 with a relationship to the Impurities. His connection with these elements are rooted deep into his being.
 * His existence is at one with the Impurities and his form is entirely composed of them. Thus, he shares their innate torment which he must suffer for as long as he exists.
 * Despite the torment they inflict on him, they are his main and only source of healing, which can be tapped into via . They are also his source of strength.
 * Additionally, they are able to grant him new lives if he dies, but the lives they give to him are said by himself to be unnatural, which he accepts nevertheless.
 * He is the self-professed guardian of the Impurities, likely an extension of his self-professed role as nature's darkest agent. He give tithes of gold to them for some reason.
 * Painfully aware of the horrible truth of it all, Leshrac seeks his own death so that he might learn the worse mysteries hidden from him by the Impurities in the afterlife.
 * Leshrac often invokes the Impurities in his actions.  When he dies, he mentions the Impurities out of lament, showing his great devotion to them.
 * Those who have been killed by Leshrac are sent back to the Impurities afterwards that they may merge with these impure elements for an agonizing fate like his own.

Resources
The Chronoptic Crystals might a conduit of the Impurities, since they channel Chronoptic energies through them, implied to be an Impurity in the “List of Impurities” section.