Omegus

Synopsis
The Omegus is the mortal name for the half of the All that encompasses chaos, oblivion, corruption, entropy and destruction. It is in itself equal to the power of Alphari. Despite being the source of destruction, it also has the power to create but typically prefers to overtake materials or creatures of the Alphari and twist them into its own idea of what reality should be (See Voiden, Unmen and Dark Mirror Shards).

The Omegus has no gender, is timeless and is universally regarded by scholars to be half of all of existence, therefore cannot be completely destroyed without destroying reality as it's known along with it. It is also not inherently evil nor dark, though many mistakenly call it so. Civilization's progress would not have happened as it did without some chaos and destruction. Omegus is a Primal Root Power, and as such is suspected to never directly communicate with anyone but the Field Marshall,  although some Dark Eldari will speak of hearing 'The Whispers' from the dark power.

Its primary weapon of choice is the Voiden Taint.

Heirarchy
Omegus is the over-arching name for all energies, entities, spirits, gods and creatures within the collective, though usually it is reserved as the name of the origin source with 'Voiden' used for the elite once-mortal footsoldiers that lead Unmen swarms (this helps mortals in their desperate urge to try and understand that which frightens or confuses them). Despite being the primal power of Chaos, there is still a recognizable heirarchy that is followed.

Other than the Prime Root,  all other ranks are made up of sentient creatures originally seduced by the power offered by Omegus' agents (also other sentient creatures) or who volunteered to give themselves over to the Chaos.
 * 1) Omegus - the Prime Root,  the half of the All that is Chaos, source of the Voiden Taint.
 * 2) Field Marshall - Leader of all Voiden and Unmen forces. The right hand of Omegus,equivalent to archangels or archdevils in classic religeon. There is only one Field Marshall at any given time, regardless of how many planes or existences that the Voiden Taint is in.  The Field Marshall is a person or sentient creature who has risen through the ranks from Unman to General.  They usually receive promotion when the existing Field Marshall is destroyed.
 * 3)  Generals - Each lead a Division of roughly 10,000 Unmen.  This division may be include lower ranking Voiden leaders.
 * 4) Captains - Each lead a Regiment of roughly 500 Unmen.  The regiment may be Voiden Lieutenants and Unmen Hunters, mixed
 * 5) Lieutenants - Each lead a company of anywhere from 20-100 Unmen.  They typically do not have any Voiden other than Unman Hunters under their direction. This is usually the first party to infest an area once it's been scouted and are the ones who work to establish a foothold.
 * 6) Hunters - The Unman Rank & File,  the grunts.  They may be new or seasoned Unmen or unproven Voiden Candidates.

Hounds of Omegus
A special force consisting of Voiden and Unmen who were Rogues, Blackguards, Assassins, Rangers and other such espionage and tracking trained skillsets exists, especially attuned to the Call of The Omegus and exclusively loyal to the Prime Root Omegus itself alone. They track those sentient beings experiencing the Call of The Omegus and either recruit or destroy them. They serve as the intelligence service of the Voiden,  and are known as the Hounds of Omegus.

Voiden vs.  Unmen and The Call of Omegus
There is often confusion on which term actually applies when referring to the creatures that make up Omegus'  armies. Voiden would be the leaders,  Unmen the maddened, mindless grunts.

Most of the time when a sentient being becomes tainted through the Corruption Spew or by purposely speaking with and listening to an Agent of Omegus, they experience The Call of Omegus. This has been described as being in a large and crowded auditorium where everyone present only speaks in whispers, causing the tainted one to have to choose whether to try and listen closer (thus giving in to The Call)  or try to ignore it. This incessant whispering drives many mad to the point of losing their minds,  which makes them perfect Hunters for The Omegus but useless for anything but swarming and being cannon fodder.

The rare few who can both withstand the madness of the whispering but who also willingly sacrifice themselves to Omegus'  power retain far more of their mortal cunning and mental willpower. These are usually not Unmen for long but are promoted by Omegus or the Field Marshall to Lieutenants, Captains and Generals as they prove their dedication.

No one really knows what the mental state of the Hounds of Omegus really is, as mixed reports have suggested they are both like wild and mad animals, but also that they are shrewd and calculating hunters with all knowledge retained from all of their lives' experiences. No Hound speaks in an audible voice beyond an eerie hiss that only the Voiden leaders and Omegus can understand.