Chaos

Chaos refers to the universal and usually malign spiritual force represented by the often malevolent intelligent entities comprised of psychic energy that live in the Warp. These entities are mostly daemons, but the term also encompasses those mortals who have thrown in their lot with Chaos, ranging from simple peasants and/or manufactorum labourers who serve as Chaos Cultists, to Traitor Imperial Guardsmen, warriors, Imperial nobles, Planetary Governors, and even the mighty Chaos Space Marines and Traitor Titan Legions of the Dark Mechanicus. Chaos is also itself the turbulent psychic energy that comprises Warpspace. Chaos is almost synonymous with the Warp - the two concepts are inseparable, for Chaos is the limitless ocean of spiritual and emotional energy that defines the Immaterium. It is a great and raw force of change and power, and is both physically and spiritually corrupting. The most evolutionarily-advanced mortals, psykers, can utilize this energy, thus making them capable of abilities which transcend the standard physical laws of the material universe as Mankind understands them. However, the malevolent power of Chaos can gradually corrupt a psyker, tainting his mind and body and turning him into the slave of the Ruinous Powers. The most powerful entities of Chaos are the four great Chaos Gods, also known as the Ruinous Powers, who each embody one aspect of the greater force of Chaos and can be worshipped individually or as an entire pantheon. The iconic symbol of Chaos is the eight-pointed star, representing the infinite possibilities of Chaos. Ultimately, Chaos and its entities seek nothing less than the complete destruction of the material universe and its hated Order, so that all of Creation is once more consumed by the primordial energies of Chaos. In general, Chaos is a malevolent spiritual force that represents the collective negative aspects of the psyches of every sentient being in the Milky Way Galaxy, and most likely in the wider universe. Because Mankind is by far the most populous intelligent species in the galaxy of the late 41st Millennium, the Chaos Gods particularly embody Humanity's myriad and particular flaws as a people.

History
At the dawn of time, the powerful and ancient alien race known only as the Old Ones nurtured some of the primitive intelligent races of the Milky Way Galaxy, guiding their development to suit a specific purpose. The Warp at this time in the vicinity of the galaxy was not the intrinsically hostile place it has become in later ages. Once the Necrons arose to challenge them and nearly wrought their extinction, the Old Ones created new psychic warrior races to battle the threat they posed, hoping that these species' stronger ties to the Warp and potent psychic powers would turn the tide against the Necrons and their C'tan masters in the ancient War in Heaven. One of these races was the Eldar and among the others were the Krork, who may have been the ancestors of the Orks.

Just before the birth of the Emperor of Mankind on Terra in the 8th Millennium B.C., three of the major Chaos Gods of the present, Khorne, Tzeentch, and Nurgle, had already begun to take form in the Warp, although it would take until the end of Terra's European Middle Ages midway through the 2nd Millennium (circa 1400 AD) for them to fully awaken. Slaanesh did not awaken until the 29th Millennium, brought into existence by the terrible collective psychic flaws of the ancient Eldar, with its birth to consciousness in the Warp marking the end of the Eldar's empire and the Age of Strife, as well as the beginning of the Emperor's Great Crusade and the birth of the Imperium of Man.

The rise of Chaos and the first three Chaos Gods seems to correspond to the rapid rise and development of humanity in the Milky Way Galaxy, implying that Mankind, of all the sentient species of the galaxy, was primarily responsible for the disharmonizing of the Warp and the birth of the first three Chaos Gods, or at least the major Chaos Gods in their current shapes. Although, without question, all the sentient species of the Milky Way played a role in the birth of the Chaos Gods, it seems that Mankind has an especially close relationship with Chaos, or that the nature of Mankind's collective psyche is particularly aggressive and unstable.

The Horus Heresy
The Horus Heresy took place after Mankind's reconquest of the Milky Way Galaxy, during the Great Crusade of the late 30th and early 31st Millenniums following the birth of Slaanesh. The Space Marines, the Imperium's elite warriors and the mainstay of the Imperium of Man's conquering armies, became divided as some turned away from the Imperium to the worship of Chaos and, led by the Warmaster Horus, turned on the Emperor's remaining Loyalist forces until they were defeated by Horus' death at the Emperor's hands during the Chaos forces' Siege of the Imperial Palace on Terra. Yet Chaos also won a victory, for the Emperor was crippled by his battle with Horus and had to be interred within the Golden Throne's life support systems, no longer truly alive or dead, sentencing the Imperium of Man to a long, slow period of decay over the next ten thousand standard years.

The Forces of Chaos
The Forces of Chaos is a term applied by Imperial scholars to all the myriad servants of the Ruinous Powers of Chaos who seek to destroy the Imperium of Man and replace it with the utterly anarchic predominance of Chaos, a state of affairs that would likely result in the eventual extinction of the human race and indeed of all sentient life in the Milky Way Galaxy were it to come to fruition. For clarity's sake, most scholars divide up the Forces of Chaos into three major components, including the inhuman daemonic entities that are native to the Warp and only rarely impinge upon the physical universe, the Lost and the Damned which includes among their numbers Chaos Cultists, Traitor Guardsmen, mutants and the other mortal devotees of Chaos and finally, Chaos' most potent servants, the Traitor Legions of the Chaos Space Marines and their counterparts among the Traitor Titan Legions of the Dark Mechanicus.
 * Daemons
 * The Lost and the Damned
 * Chaos Space Marines

Khorne, the Blood God
Khorne is the Blood God, the God of War, Murder and Violent Death. He draws his power from the blood and skulls collected for him by his followers. The sheer amount of bloodshed and death in the galaxy currently has made Khorne the most powerful Chaos God. He sits upon a brass throne, which rests on a massive mountain of skulls, each taken in his name by a devotee. In every direction, as far as he can see, the ground is covered with shattered bones and rotted corpses. As the god of battle, Khorne bestows his favor on those who demonstrate martial prowess. Great warriors are often subjects of Khorne's interest. The followers of Khorne are almost all uncontrollable fighters who excel at the art of killing. His warhosts count many savage Chaos Space Marines and mutant warriors among their numbers. Khorne's followers share their god's straightforward philosophy on warfare, preferring to charge directly at their foes in order to defeat them in close, usually melee combat. As such, Khorne's followers are generally berserkers that pay little heed to tactics or defense in their frenzy for blood. Khorne frowns upon the use of sorcery, psychic powers and trickery, and those who use sorcery or are psykers should look elsewhere to find a patron for their studies. Khorne is the most powerful of the Chaos Gods, given that he is empowered by war and fighting, and given the ceaseless conflict in the Warhammer 40,000 universe he gains power constantly. Khorne is a god of war who acts outwardly by seeking the death of others, preferring close combat over ranged weaponry; as such, he is completely opposed to the hedonistic Slaanesh, an inwardly acting god who seeks pleasure in every act and experience. He has a strong distrust of sorcerers and psykers, whom he sees as cowards; this means he is also highly suspicious of Tzeentch, although they are not archenemies.

Nurgle, the Plague Lord
Nurgle is the God of Disease and Decay. He is the embodiment of the hungry earth, the carrion crow whose poxes and plagues are inflicted upon all. Nurgle's power waxes and wanes over time as his "gifts" to the myriad worlds are spread, are cured or simply kill off everything in sight. Many of Nurgle's victims will eventually turn to his worship in the hope that it will ward off or ameliorate the torment they suffer at his hands. For entertainment, Nurgle will orchestrate plagues and new diseases, such as the Plague of Unbelief (Zombie Plague) and watch bemusedly as the mortals struggle to fight the illness and develop a cure. Many of Nurgle's wars are won indirectly simply through the plagues that sweep that land before his armies. Of note is Nurgle's rot, which gradually changes a victim into a Plaguebearer. Nurgle's followers tend to have a strong interest in the spread of disease. His worshippers become infected with horrific diseases which cause them to appear as disgusting, bloated and rotting masses of barely recognizable flesh, with many sores and open wounds in which infection and decay is rampant. Occasionally Nurgle's followers may become wizened, sickly thin and pale, while still having great power over disease. His Champions become so mutated and putrid that they are impervious to pain and almost impossible to injure. While equal in power with Khorne and Tzeentch, Nurgle's power is much less stable. At times, his forces are limitless and unbeatable, numberless rotting armies scouring the land of life. At others, his followers are scattered and weak, hiding in fetid corners of the universe. Nurgle's strength lies in stagnancy and decay, as well as the emotion of despair, which puts him in direct opposition to Tzeentch, who embodies hope, ambition and change.

Slaanesh, the Dark Prince of Chaos
Slaanesh is the Dark Prince of Chaos, the God of Pleasure and Pain. Slaanesh is the beguiling water, the Great Serpent who lives for pleasure and the experience of the sensations of life and death. All those who live in the pursuit of pleasure risk falling under this god's deceptive charms. Slaanesh is the youngest of the Chaos Gods, and referred to by the other Ruinous Powers as the Prince of Chaos. Seductive in the way that only an immortal being can be, Slaanesh is the Chaos God of pleasure, passion, luxury, art, and indulgence. Slaanesh is the manifestation of all hidden vices, cruel passions, and secret temptations that men hide fearfully in their hearts. While not interested in the dirty warfare of Khorne, (Khorne and Slaanesh are mortal enemies, as Slaanesh acts inwardly upon the mortal psyche by seeking selfish pleasure, while Khorne acts outward to kill others) Slaanesh does enjoy combat of the artistic sort, rewarding those whose fighting is transformed from a means to an end and thus into an art form all its own. Slaanesh's followers seek pleasure in every experience, and quickly become inured to more mundane things, including sounds and colors; thus they frequently wear garish, brightly colored armor, or clothing which is extravagantly decorated. Worshippers of Slaanesh are known for their complete lack of fear, as they see losing a battle as a new experience to be enjoyed. Slaanesh is the youngest and weakest of the major Chaos Gods. However, Slaanesh is constantly growing in power due to the corrupt and dark nature that all sentient beings, but particularly the Eldar and Mankind try to keep hidden within their hearts, for even the mere act of thinking about such dark acts of pleasure and vice are enough to give spiritual strength to Slaanesh. It won't be long before Slaanesh sits as an equal of power amongst the other three Ruinous Powers, and may even rise above Khorne, given time and the incessant quest across the galaxy for pleasure.

Tzeentch, the Changer of Ways
Tzeentch is the Changer of Ways, the God of Change and Dark Knowledge. Tzeentch is the inconstant air, the Great Eagle who pulls the strings of fate in whichever way he pleases. The minions and followers of Tzeentch manipulate the sorcery and psychic power of the Warp in their rawest form, and often know the thoughts and fates of their foes even before they do. Not interested in raw strength, Tzeentch bestows his favor upon those who use their intelligence to fight their enemies. Mortal worshipers of Tzeentch tend to be sorcerers, psykers, scholars and other educated elites who desire greater knowledge and power. Some of these worshipers become very powerful sorcerers, but Tzeentch has a tendency to mutate his followers, and the highest levels of power are said to be difficult for his followers to reach, as they frequently find themselves mutated into mindless beasts like the Chaos Spawn. Those who do attain great power in the service of Tzeentch, however, are extremely powerful foes who are often mighty sorcerers as well as great warriors. Tzeentch is as powerful as Khorne, but with a different style of power, controlling sorcery and psychic power instead of armies. The plots of Tzeentch are countless, and whenever there is an alliance of Chaos Undivided forged by the Gods of Chaos, Tzeentch is undoubtedly the cause, direct or indirect. Tzeentch also represents optimism, hope and the willingness to change, thus making Nurgle his nemesis.

Malal, the Renegade God
Malal is the renegade God of Chaos, the God of Contention and Anarchy, the sworn enemy of the other four Chaos Gods and all they represent, though he is no friend of Mankind, either. He represents the absolute anarchy of true Chaos and its tendency to turn even upon itself in its own randomness. He is, however, absent from the most recent editions of all the Warhammer games for copyright reasons.

Chaos Undivided
Followers of Chaos Undivided venerate the force of Chaos itself, seeing the four major Chaos Gods as a single pantheon to be worshiped equally as different emanations of the same universal force. Of all the worshipers of Chaos they follow Chaos in its purest form. They can interpret the meaning of Chaos in a variety of ways, including as a single god, worship the four major Chaos Gods equally, or favor one slightly over the others. The Chaos Lords and Daemon Princes of Chaos Undivided are at an advantage in their ability to unite any of the Forces of Chaos under their leadership, even if they would normally worship opposing gods like Khorne and Slaanesh, so the warbands of Chaos Undivided are always the most diverse. The majority of the Traitor Legions worship Chaos Undivided, including the feared Black Legion of Abaddon the Despoiler, the greatest Champion of Chaos Undivided.

Imperial Secrecy
To protect its citizens from the insidious temptations of Chaos, the Imperium of Man does its best to hide the existence of daemons and the Chaos Space Marines from public knowledge. Only Space Marine Chapters, Imperial Guardsmen, Sanctioned Psykers and the members of the Inquisition are permitted to know the Imperium's darkest secret. All others are either put to death, or if they have been a valuable servant to the Imperium, undergo memory modification or even, in extreme cases, a mind-wipe. This is a policy that has been in place since before the Emperor of Mankind was interned on the Golden Throne, when only he and his Primarchs knew that the Warp contained intelligent entities capable of possessing individuals in realspace. But even the Emperor did not reveal to his Primarchs the truth that the Warp was not just a seething cauldron of chaotic psychic energies, but was actually populated by malign intelligences similar to the supernatural beings of ancient human myth and superstition that were the Ruinous Powers of Chaos and their daemonic servants.