The Void appears to bear a breathable atmosphere to creatures of the material universe. The Void has borne its own lifeforms, such as the xel'naga,Void shades, and possibly other species. Landforms exist inside the Void, akin to floating islands. "Currents" of the Void can be accessed from the material universe, said currents being affected by gravity and solar winds.
Void energy is highly unpredictable, and in sufficient quantity is lethal to both protoss and zerg, and can blind the sensors of the former species.
"The Void is not like the Khala. It does not draw us together and connect us in a blanket of warm feelings. The Void certainly does not offer itself willingly. A dark templar stalks the Void and, through will and discipline, forces it to give up its power."
The Void is understood by the Nerazim. Due to severing their nerve cords in a display of contempt for the Conclave, they lost the primal link the rest of the protoss share, and removed them from the control and discipline the Khala provides. Forced to live in secrecy to avoid detection by the Khalai, and without the psionic focus afforded by the Khala, the Nerazim were forced to delve into the mysteries of the Void, eventually learning how to wrest its power by means of rigorous training, discipline, and will.
The Void provides the Nerazim with psionic powers unheard of by their brethren and grants them enormously strong individual will. They require great will and discipline to make use of the Void, and can be consumed by it if they do not possess these traits. Those who walk this path do so with diligence and reverence, for they know full well the dangers lurking in the shadows of the Void.
The "currents" of the Void allow faster-than-lightspeed travel for the Dark Templar. Strands of the Void can be wielded by a Nerazim, separating it into numerous strands if they so desire.
Void powers enable Dark Templar to resist infestation by the zerg. The particle disrupters mounted on stalkers use the power of a Nerazim to shoot entropic Void energy at targets;Tal'darim stalkers' have been observed to fire green projectiles, as opposed to the usual blue fired by their Daelaam counterparts.
The warp blades utilized by Nerazim warriors are infused with Void energy.
The Nerazim appear to associate the Void with death or the afterlife – to "embrace the Void" is to embrace death, so to speak. They consider anything that taints the Void to be unholy, and it is a major part of their religion. When the Nerazim began studying the Void they wrote texts on the subject, said texts becoming the basis of their teachings on the subject centuries later.
During the Second Great War, certain Dark Templar mentioned "an ancient voice whispering from the Void," chilling them to the core.
Utilizing the Void and Khala simultaneously grants protoss incredible power, but can result in the protoss burning out like a star. Protoss who can utilize both sets of power simultaneously are exceedingly rare. Known practitioners were Adun and Tassadar. Similarly, the prismatic core of the void ray draws upon the powers of the Void and Khala in tandem, forming a self-sustaining reaction and thus making the core a virtually eternal power source.
The Tal'darim believe that Amon resides within the Void, and it is only through His blessing that one is able to travel through it. It is from the Void that they draw energy for their psi-blades. In addition, they regularly use terrazine, a substance originally from the Void, to enhance their powers.
The xel'naga arose within the Void and understood their domain. Their ships possessed the ability to travel through it. The xel'naga imprisoned the KL-2 entity using the powers of the Void. When their physical bodies are killed, their minds survive within the Void, and they can be revived with enough psionic energy, as happened with Amon. As such, the only way to truly kill a xel'naga is to destroy it in the Void.
↑Yeah, I mean, basically, any protoss that is a part of the Khala is going to have an enormous psionic energy to draw on and can create, you know, obviously, wepons and blades with it. The dark templar, you now, in all of the lore, they, because they chose to go their own way and they don’t have the power of the Khala behind them, but they have the power of enormously strong individual will. It's sort of, I’m giving a long-winded version of the answer, I think, that Chris just gave. One is pulling that power from within whereas the dark templar have to take what is around them, the void, and manifest it. It is a completely different philosophy, but both are really cool weapons. Chris Metzen, Brian Kindregan, StarCraft Legacy staff. 2010-10-23. BlizzCon 2010 StarCraft II Lore Panel. StarCraft Legacy. Accessed 2010-10-25.