“There can be no bystanders in the battle for survival. Anyone who will not fight by your side is an enemy you must crush.”
–Lord Solar Macharius
The enemies of Mankind are countless in number and form, ranging from creatures that dwell in the depths of interstellar space and can swallow entire worlds, to legions of ravening killers intent upon desecrating humanity’s every achievement. Some are environmental, such as death worlds where every life form in the entire biosphere is dedicated to slaying any intruder. Others come from within, such as when a trusted leader turns his back upon the Emperor and seeks to name himself master of his own domains. The vast majority of threats to the continued existence of Mankind can be assigned to one of three great enemies-the enemy within, the enemy without, and the enemy beyond.
The soul of Mankind is bound to the Emperor not by unconditional reverence, but by the rule of the Imperial Creed. Though it takes as many specific forms as there are planets or even cultures in the Imperium, the one, true faith unites every man, woman, and child, every scribe, worker, and soldier, every noble, planetary governor, and High Lord. Those who would deny their duty-to the Imperium, to the Emperor, or simply to the overseer of their workplace-are deemed “heretic,” the enemy within, and cast out from the beneficence of the Emperor.
Heresy takes a myriad of forms, often varying drastically from one culture to another. Expressions of faith made on one world might be condemned as blasphemy on another, and while interplanetary travel is rare, when strangers from such divergent cultures do meet, conflict is not uncommon. When worlds are isolated for prolonged periods, the doctrines of faith are wont to diverge and mutate. Sects rise, and formerly proscribed cults step out from the shadows and preach openly to the masses. Such blasphemy against the Master of Mankind can lead ultimately only to the worship of other, darker entities: Chaos.
Those who turn to Chaos are forever damned, and in their damnation they endanger all of humanity. Some believe themselves to be sowing seeds of purity and truth as they denounce the hated corpse-god of Mankind. Others are warriors who find in the service of the Ruinous Powers the means to unleash undreamed-of destruction on their enemies. Most terrible of all those who fight for the glory of the Ruinous Powers are the Chaos Space Marines. Once ranked amongst the mightiest of the Emperor’s champions, these traitors turned against their master and creator ten thousand years ago and continue their Long War even into the current days of the Time of Ending.
The more outwardly visible expression of the taint of heresy is that of mutation and deviation from the divine form of Man. While the Imperium tolerates certain genetic divergence-sub-species such as the brutish Ogryns or diminutive Ratlings, and mild mutations to be endured within the depths of a hive factory or on fringe worlds-these exceptions are rare. Most mutants are hideous creatures tainted in both body and soul, bearing distended limbs or oversized appendages, tentacles, claws, or countless other hideous signs of some unknown sin. Some worlds use the more easily controlled mutants as expendable slave labour, while others exterminate them wholesale in fiery pogroms and wars of faith.
Many mutants display their heresy in bodily form, but the more insidious mutants possess mental aberrations, and are decried as witch, sorcerer, Warp-dabbler, or, more commonly, psyker. Each year, ever more psykers are born or come into their powers, but the vast majority are entirely too weak to control their abilities. If allowed to exist unchecked, they bring down death and destruction on their communities, as some can slay with a mere glance or blast sheets of flames from an outstretched hand. Worse, psykers cannot help but attract the attentions of the denizens of the Warp, for their powers are fuelled by a special connection to that unreal dimension. Unable to fend off such unholy predators, the psyker falls victim to possession, and his mind can become a gateway through which the Daemons of the Warp burst forth into reality. Such daemonic incursions all too often lead to the death of entire worlds and even systems.
The second of the trinity of threats to Mankind’s dominion over the stars is the alien. While the Imperium stretches from one side of the galaxy to the other, it can never hope to maintain discrete borders. Within this enormous volume of space are innumerable star systems and worlds, the vast majority of which have never been explored. The million or so worlds that fall under the direct rule of Terra must be measured against the hundreds of billions of stars in the galaxy. In between each lies the trackless black void, hiding all manner of blasphemous and horrifying forms of life.
Entire alien empires rise and fall in the depths of space, some never coming into contact with the Imperium of Man. Many xenos species never develop the means to leave the world of their birth and may vanish into extinction, leaving only bones and ruins to mark their passing. When a technologically advanced culture and the Imperium encounter one another, the result is almost always bloodshed on an enormous scale. Such conflicts invariably spell the doom of the xenos, for the one resource the Imperium possesses in limitless reserves is men. Though it cost the lives of billions, once mobilised to war almost nothing can stay the Imperium’s hand. Yet some races resist their rightful extermination and are persistent dangers to Mankind.
Heavily muscled, brutal, and crude, Orks can be found everywhere across the galaxy, possessing a barbarous cunning and innate empathy for war. United under a single leader, countless millions of bellowing green-skinned warriors take to the stars aboard ramshackle warships in migrations known as the “Waaagh!” to set entire sectors alight. The Eldar are the fading remnants of a once-great empire, divided into those who dwell within world-vessels and their cruel kin in extra-dimensional lairs. All regard Mankind as crude interlopers and flee the doom of their species at the hands of the Chaos God Slaanesh, “She Who Thirsts,” created by their own ancient folly.
Endless other xenos assail the Imperium. The ravenous Tyranids invade from the dark space beyond the galaxy’s eastern edge, their Hive Fleets acting as a gargantuan slavering mouth closing upon its prey. The Tau are a technologically advanced species determined to spread their doctrines across the stars. Finally, the Necrons are a race of metallic warriors who have slumbered in stasis-tombs for millions of years and are only just awakening to reclaim their lost heritage.
The third, and undoubtedly the worst of the three great threats to the soul of Mankind, is that which seethes and gibbers but a thought away in the unreal dimension of the Warp. Without the Warp, the Imperium would cease to meaningfully exist. It is only by voyaging through the Sea of Souls, where the rational laws of time and space have no meaning, that it is possible to maintain a galaxy-spanning empire at all. Equally, Mankind relies upon those gifted with psychic powers for interstellar communication. Control over the worlds of the Imperium would be impossible without the Warp.
But as much as the Warp is the basis of Mankind’s dominion over the galaxy, it is also the crucible of its doom. The Warp can be likened to a raging sea made from the raw stuff of the soul. All mortals blessed with a soul have a connection to the Warp, but souls most are insignificant and offer poor sustenance to the predators that lurk within its depths. It is via the soul that the beings within the Warp interact with the physical universe, poisoning the hearts and minds of men with the unutterable madness that is their being. The connection flows both ways; for mortal passions feed the Warp, and from these concentrated storms of emotion came sentient creatures of horrid design. These are the Chaos Gods, manifestations of the worst excesses of living creatures. They are the secret that humanity must never know, for the knowledge of the Warp’s true nature and this soul-consuming threat would drive men to madness.
The Chaos Gods are raw desire, rage, decay, and hubris, and from terrible kingdoms within the Warp reach out to Mankind to entice and destroy. There are four great Chaos Gods: the Blood God Khorne, the God of Decay Nurgle, the Prince of Desire Slaanesh, and the Master of Fate Tzeentch. These Ruinous Powers await the deluded and desirous, granting power in exchange for souls to those who would betray their Emperor. Serving these terrible entities are their legions of Daemons. These creatures of raw Warp energy can emerge from the Immaterium to form corporeal bodies and directly kill, tempt, and enrapture mortals. Each is an impossible shape, baleful to the mind and imparting soul-wrenching fear upon all who see them. Some are summoned through foul ritual, eagerly venturing into reality and often consuming the souls of those who would seek to bind them. Others pierce the breach between real space and the Immaterium through locations weakened from bloody warfare or uncontrolled psychic emanations. Once unleashed, Daemons are an affront to reality and, until banished back to the Warp, are a danger few can comprehend, let alone withstand.
A few are mortals raised up to the status of immortal Daemon Princes, the reward for exceptionally perverse and dedicated service to their profane god. The vast majority who tread the Path to Glory have not the strength to contain the mutating power of the Warp, however, and are transformed into Chaos Spawn: mindless beasts of tentacle and claw, forever a lesson on the fickle nature of the Ruinous Powers.