The Long War is what the Chaos Space Marines call their ongoing war against the Imperium, the fight Horus started during the Horus Heresy and that they’ve never stopped. It’s the thread that ties the traitor legions to the Black Crusades and to everything they do in the 41st millennium.
What the Long War actually means
For the Imperium, the Horus Heresy is ancient history, a myth wrapped in ten thousand years of dogma. For the Chaos Space Marines who fled into the Eye of Terror, it isn’t. The Warp messes with time, so some of them lived through the Heresy only days or centuries ago, while others have been fighting it for far longer than realspace has existed.
That gap is the whole point. The Long War is their name for the grudge match they refuse to let go, the unfinished business of toppling the Emperor and finishing what Horus began.
Why it matters
Most of the traitor legions have splintered into warbands, warlords, and daemon-ridden killers who care more about the Great Game in the Warp than the Imperium. The Long War is one of the few things that can still pull them together. When Abaddon the Despoiler calls a Black Crusade, it’s the Long War that gives the disparate warbands a shared cause.
A lot of Chaos Space Marines also see the daemon primarchs as quitters. In their eyes, Horus’s old brothers gave up on the Long War by ascending to daemonhood and turning their attention to the Warp instead.
How it connects to the wider lore
The Long War is the bridge between the Horus Heresy and the modern setting. It explains why the Chaos Space Marines are still a threat ten millennia later, why the Eye of Terror keeps spitting out warbands, and what the Black Crusades are actually for.
It also gives the traitor legions a motive beyond simple madness. Even the ones who’ve lost themselves to the Warp are still, in some sense, fighting the same war.
Key facts
- The Long War is the Chaos Space Marines’ name for their ongoing war against the Imperium.
- It began with Horus during the Horus Heresy and never officially ended.
- Time in the Eye of Terror is inconsistent, so some traitors remember the Heresy as recent.
- The Long War is one of the few causes that can unite rival warbands.
- Abaddon’s Black Crusades are the most visible expression of the Long War.
- Many Chaos Space Marines consider the daemon primarchs to have abandoned the cause.
FAQ
Who started the Long War?
Horus Lupercal started it during the Horus Heresy. The Chaos Space Marines who survived kept it going after his death.
Is the Long War the same as the Horus Heresy?
No. The Heresy was the opening act. The Long War is everything the traitors have done since, including the Black Crusades.
Why do Chaos Space Marines still fight it?
For some it’s purpose, for others revenge, and for many it’s the only thing that keeps them from fully losing themselves to the Warp.