Chaos Gods

In the Aeon of the Champion story series, the Chaos Gods (also referred to as the Dread Elders or Great Old Ones) are parasitic eldritch horrors that terrorise Reality, as physical manifestations of the Void's power. Created by the Dark Cosmics as a reactionary manoeuver against the Formation and Ordering of the Universe. Feeding off of the nourishing energies of the planets that they come to inhabit, the ultimate objective of the Chaos Gods is to find a world that will supply them with enough power to create a tether between the Void and Reality, which will facilitate the crossover of the Dark Cosmics into the real Universe; they will proceed to undo the effects of the Creation and bring the entire cosmos collapsing in on itself.

History
The Dark Cosmics watched the work of the titans from their home dimension, the Void, with rage and hurt building up inside them. The Universe was being formed and ordered, and Dark Cosmics did not enjoy it one bit. In their eyes, a chaotic and disorderly universe was the best type of universe, and any attempt to impose order on realspace was a violation not only of the laws of nature, but also of all that is to be considered rational. Knowing they could not manifest in the physical world without tremendous power at their disposal, the Dark Cosmics decided that they would find a way to take control of those power sources, with which they could then enter into the physical world unrestrained.

And thus, they merged their energies together and tossed the resultant creations throughout the cosmos, hoping that they would collide with as many planets as possible. Many planets within the Great Unknown were touched by their blighted forms during these attacks, and the Chaos Gods, upon entering each planet, brought waves of darkness and despair crashing down as the influence of the Void gained a foothold on them. They pumped out arcane lifeblood and spirit energy, and pumped in Void toxins.

While many of the gods entered regular planets, a select few of them entered into chaos planets, found only in the Nether. These planets, while extremely dangerous, contained a diverse array of energies and magics both natural and unnatural, the perfect source of nutrition for the ever-hungry Chaos Gods. Thus, they immediately put these planets to good use. Turning the chaos planets into voidworlds, which attracted a race of vampiric demons known as Bajangs (then referred to as Darklings) to the surface of the worlds. One such world was Euratius, which was in close proximity to the interface of Reality and the Nether. The constant fission action at this chaotic site eventually tore a hole in the fabric of the universe, causing its energies to partially spill out (interdimensional taint).

At the same time, Lucithel was touring the cosmos on his own, having temporarily strayed from the Elysian Fields. His main targets were demons, who originated from the Nether anyway (though he didn't know where this was). It was only when he saw the gaping tear in the Great Unknown that he sensed something was awry, and, after making the fateful decision to venture inside, saw the fate of Euratius - a realm so twisted and ugly, it could only be home to terrible things. An interrogation of the Darklings confirmed his worst fears, and it is this event that prompted him to destroy Euratius and b) call for an end to the Great War between Elysium and Tartarus, stating that the Void was a greater threat than the demons ever would be. After being rebuked by Aesir on the Aegis Council of Archangels, Lucithel abandoned his brethren for good and, becoming the fanatical demonlord Sargamon, created the Marching Horde to destroy all life, with the intention of preventing the Dark Cosmics from having any sources of energy with which to transport into Reality.