The Primarchs: Warhammer 40K Lore Guide

The Primarchs are the twenty sons of the Emperor of Mankind: gene-forged demigods built to lead humanity's conquest of the galaxy. Each was a general, a warrior and a statesman beyond any mortal, and each gave his genetic legacy to a Legion of Space Marines. Half of them betrayed their father. Ten thousand years later, some are dead, some are missing, some have become daemons — and a few have come back.

Every Chapter in our Space Marines (Adeptus Astartes) guide traces its gene-seed to one of these beings, and so does every Traitor Legion. This guide explains how the Primarchs were made and lost, how they were found during the Great Crusade, which side each chose in the Horus Heresy, the mystery of the two missing Primarchs, and the status of every surviving son in the 42nd millennium. Each Primarch also has his own in-depth guide, linked in the table below.

The Primarchs at a Glance

Creation and Scattering

Before the Great Crusade, the Emperor of Mankind poured His genius and part of His own essence into twenty gestation capsules hidden beneath the mountains of Terra. Each Primarch was meant to embody a different facet of what humanity needed — strategy, endurance, fury, faith, stealth, craft — and each would command a Legion grown from his own genetic template.

Before the project was complete, the Chaos Gods struck. A warp event ripped the infant Primarchs from the laboratory and scattered them across the galaxy. The lore has always hinted that this was no accident and that the Ruinous Powers had marked the Primarchs from the start. The Emperor salvaged what He could: from the Primarchs' gene-seed He created the twenty Space Marine Legions, and launched His Crusade to reclaim the stars, hoping to find His sons along the way.

Each infant landed on a different world, and each world shaped him. Konrad Curze grew up alone in the lightless crime-city of Nostramo; Angron was enslaved as a gladiator on Nuceria; Guilliman was adopted by a ruling consul on Macragge; Leman Russ was raised among the tribes of Fenris. Those childhoods explain much of what each Primarch became.

Reunion: The Great Crusade

One by one, the Emperor found His sons. Horus was the first, discovered on the mining world of Cthonia, and he fought beside his father for years before any brother joined them. Alpharius was the last. Each reunited Primarch was given command of his Legion and a share of the Great Crusade, and for a few decades the Imperium knew something close to a golden age.

The Primarchs were not equals, and they were not always brothers in anything but name. Rivalries ran deep: Dorn and Perturabo resented each other; the Lion and Russ came to blows; Curze's visions and Magnus's sorcery isolated them. When the Emperor withdrew to Terra and named Horus Warmaster, those cracks became the fault lines of a civil war.

All Twenty Primarchs: Legions, Allegiance and Fate

The table below lists every Primarch in Legion order, with his Legion, his side in the Horus Heresy and his fate as of the current setting.

The Lost Primarchs: II and XI

Two numbers in the list are blank. The II and XI Legions and their Primarchs were deliberately removed from Imperial records, and Games Workshop has never revealed who they were, what they were called, or what happened to them. Even within the setting, the information was purged so thoroughly that almost no one remembers.

What the lore does establish is limited: both Primarchs existed, both were lost before the Horus Heresy, and the records of their Legions were expunged, apparently on the Emperor's authority. Black Library's novels occasionally have characters allude to the missing brothers, usually as a warning, but never with names or a full explanation. Everything else — fan theories about failed Primarchs, Chaos corruption or hidden Legions — is speculation. The empty slots are part of the setting's design: a reminder that even the Imperium's founding myth has been edited.

The Horus Heresy: Brother Against Brother

When Horus rebelled, eight of his brothers followed him: Fulgrim, Perturabo, Curze, Angron, Mortarion, Magnus, Lorgar and Alpharius. Their reasons were wildly different. Lorgar sought a faith the Emperor had denied him; Angron was already broken by his slave-implants; Magnus was driven into Horus's arms by the destruction of Prospero; Curze despised the Imperium he had seen in visions; Alpharius claimed to be serving humanity by joining the enemy. The Horus Heresy was therefore not one rebellion but nine, each with its own logic.

The war killed or broke many of the Emperor's sons. Ferrus Manus died at Isstvan V; Sanguinius died aboard the Vengeful Spirit; Horus died at the Emperor's hand. Most of the surviving traitors embraced their patron gods and ascended as Daemon Primarchs, while the loyalists divided the Legions into Chapters under Guilliman's Codex Astartes.

After the Heresy: Missing, Dead and Returned

In the centuries that followed, the loyal Primarchs vanished one by one. Guilliman was poisoned by Fulgrim's daemon blade and frozen in stasis on Macragge. The Lion was gravely wounded fighting Luther and the Fallen on Caliban and vanished; it later emerged that he had been sleeping deep within the Rock. Russ left on a final hunt, the Khan rode into the Webway, Corax entered the Eye of Terror, and Dorn was lost in battle against the traitors. By the 41st millennium, the Imperium had no living Primarch to lead it.

That has changed. Roboute Guilliman was resurrected at the start of the Great Rift era and now leads the Imperium as Lord Commander. Lion El'Jonson awoke and returned to fight in the war-torn Imperium Nihilus. Vulkan, a Perpetual whose deaths have never been permanent, has not yet returned, but the Salamanders still search for him. On the other side, Magnus, Mortarion, Angron and Fulgrim have returned to lead their Legions as Daemon Primarchs, and the Emperor's sons once again stand on opposite sides of a galactic war.

The Primarchs on the Tabletop

In Warhammer 40,000, a handful of Primarchs are playable as huge centerpiece models: Roboute Guilliman and Lion El'Jonson for the Space Marines, and the Daemon Primarchs Magnus, Mortarion, Angron and Fulgrim for their Chaos Legions. Each is among the most powerful single models an army can field, built to dominate the table and anchor the force's theme.

Games Workshop's Horus Heresy game goes further, offering Primarch models for the Legions as they were during the war, before most of them fell or vanished. Collecting your Legion's Primarch is a rite of passage for many Heresy players. If you are building your own Chapter, the Space Marine name generator can help you name the heroes descended from your chosen Primarch.

Primarchs FAQ

How many Primarchs are there?

Twenty. Eighteen are known by name; the II and XI Primarchs were erased from Imperial records, and their identities have never been revealed.

Which Primarchs are still alive in Warhammer 40K?

Roboute Guilliman and Lion El'Jonson are alive and active for the Imperium. Magnus, Mortarion, Angron, Fulgrim, Perturabo and Lorgar endure as Daemon Primarchs. Leman Russ, Jaghatai Khan, Corvus Corax and Vulkan are missing, and Alpharius's fate is disputed.

Which Primarchs turned traitor?

Nine: Horus, Fulgrim, Perturabo, Konrad Curze, Angron, Mortarion, Magnus, Lorgar and Alpharius. All led their Legions against the Emperor during the Horus Heresy.

Who are the missing Primarchs?

The two "lost" Primarchs are II and XI, whose records were expunged before the Heresy. Separately, three loyal Primarchs are missing in the current era: Leman Russ, Jaghatai Khan and Corvus Corax.

Who was the strongest Primarch?

There is no official ranking. Horus was the most capable overall and defeated Sanguinius, though he was then empowered by Chaos. Sanguinius, Angron, the Lion, Russ and Magnus are often cited by fans for raw combat or psychic power, while Guilliman and Dorn are celebrated for strategy and defense.

Who was the first Primarch found?

Horus Lupercal, found on Cthonia, was the first Primarch reunited with the Emperor. Alpharius was the last.

Continue Exploring

• Space Marines (Adeptus Astartes) — the Legions and Chapters born from the Primarchs' gene-seed
• The Horus Heresy — the war that split the Emperor's sons
• The Emperor of Mankind — the father who made them
• Chaos Space Marines — the Traitor Legions and their fallen fathers
• Warhammer 40K Factions: Complete Guide to All 29 Armies — every army, its lore and how it plays

Browse every guide in the Warhammer 40K lore hub, or name your own Legionaries with the Space Marine name generator and the Chaos Space Marine name generator. To chronicle your own Legion and its Primarch, Anima is free and runs in your browser with no account: a wiki, a timeline, and campaigns with a live DM screen.