The Traitor Legions: Chaos Space Marines

The most dangerous enemies of humanity were once its greatest champions. The Chaos Space Marines are the fallen brethren of the loyal Adeptus Astartes — transhuman warriors who were forged to defend the human race and who chose, instead, to betray it. Ten thousand years have passed since their treachery, and in all that time their hatred has not cooled. They call their unending campaign the Long War, and they intend to see it through to the bitter end.

The Great Betrayal

Their fall began with the Horus Heresy, the civil war that nearly destroyed the Imperium at the dawn of its history. In an age when the Emperor still walked among mortals, he entrusted his grand crusade to twenty superhuman sons, the primarchs, each commanding a Legion of Space Marines. It was his most beloved son, Horus, whom he named Warmaster — and it was Horus who turned.

Seduced by the promises of the Dark Gods, Horus led half the Legions into rebellion. Brother slew brother across a thousand worlds; the war climaxed in a horrific siege of the Emperor's own palace on Terra. Horus was cast down, but the Emperor was mortally broken in the doing of it, interred forever in the machine that keeps him barely alive. The traitors, defeated, fled — and where they fled would define them forever.

Into the Eye

The broken Legions retreated into the Eye of Terror, a vast wound in reality where the material universe and the warp bleed into one another. It is a place where the laws of time and physics dissolve, and living within it changed the traitors utterly. Sheltered in that hellscape, they escaped the death that history would otherwise have dealt them.

Time runs strangely in the Eye. For the galaxy outside, ten thousand years have crawled past; for many of the traitors, far less has been felt. Warriors who fought at the Emperor's palace still live, their wounds still fresh, their fury undimmed by the millennia. This is why the Long War never ends — for its oldest veterans, the betrayal happened barely a lifetime ago, and the grudge is as raw as the day the Warmaster fell.

The Gifts and the Curse

In the Eye and in the service of the Dark Gods, the traitors changed. Some were rewarded with terrible power, their bodies reshaped into things mighty and monstrous. The most favoured champions may ascend to become Daemon Princes, immortal and dreadful. But the same power that elevates can also destroy: those who take too much, or please their patrons too little, are twisted into mindless Chaos Spawn — a shapeless ruin of flesh, a warning of what every ambitious champion risks becoming.

This is the bargain at the heart of Chaos. Power is real and freely given, but it is never free. Every gift binds the taker more tightly to gods who care nothing for them, and the line between rising to glory and dissolving into monstrosity is thinner than any champion likes to admit.

Legions and Warbands

Several of the original Traitor Legions have grown so distinct in their devotions that they stand as powers in their own right. The World Eaters gave themselves wholly to the Blood God, becoming crazed berserkers who live only to kill. The Death Guard embraced plague and decay, rotting yet unkillable in the service of the Lord of Decay. The Thousand Sons traded flesh for sorcery, masters of the psychic arts bound to the Changer of Ways. The Emperor's Children fell to obsessive excess and the worship of the Dark Prince.

Others never bound themselves to a single god. Countless smaller warbands roam the galaxy, from the survivors of Legions scattered by defeat to freshly turned renegades who abandoned the Imperium only yesterday. Some serve one power, some court all four, and some simply take what they can from a galaxy they feel owes them everything.

The Warmaster Reborn

The traitors found new unity under Abaddon, the successor to Horus and self-proclaimed Warmaster of the age. Where lesser lords squabble among themselves, Abaddon has bent his will toward a single purpose: the utter destruction of the Imperium his primarch failed to topple. Again and again he has led vast Black Crusades howling out of the Eye of Terror to ravage the human realm.

His greatest triumph shattered the galaxy in two. By tearing open a colossal rift in reality that split the Imperium along its length, Abaddon accomplished what ten thousand years of raiding never could — plunging half of human space into darkness and bringing the Long War closer to victory than it has ever been. The Warmaster's shadow now falls across the whole galaxy.

The War Without End

The Chaos Space Marines are humanity's guilt made flesh — proof that even the mightiest defenders can be turned, and that the enemy within is always the deadliest. They cannot simply be killed off, because the warp that spawns them is eternal, and every fresh betrayal, every ambitious lord who sells his soul, swells their ranks anew. Where there is despair, there is Chaos, and the galaxy has never been short of despair.

For ten thousand years the traitors have waited, and now, with the galaxy split and the Imperium reeling, they scent victory at last. The Long War grinds on, older than nations and colder than the void, and its warriors want nothing less than to see the Emperor's realm burn to ash. Whether they finally achieve it or fail as their Warmaster once did, they will never, ever stop trying.