Glossary

A xenos blade of Kinebrach make, dedicated to Nurgle — a weapon whose wounds cannot be healed. Erebus stole it from the human Interex, and with it Horus was wounded on the moon of Davin; this wound became the pretext for his seduction into Chaos.

The double-headed eagle — the crest of the Imperium. In the era of the Heresy exactly one Legion has the right to bear the Palatine aquila on its armour — the Emperor’s Children: the Emperor granted it to the III Legion for the Proximan Betrayal, in which the cohort attached to them fell to the last man beside the Custodians. The other Legions wear the “Imperialis” — the winged eagle as an army badge; all the loyalists will receive the aquila only in the wake of the Heresy. The defilement of the eagle is a gesture of treason; among the Shattered Legions a scorched badge becomes a mark of recognition for those who have not surrendered.

A psychic beacon on Terra, powered by a choir of thousands of psykers (up to a hundred burn out every day) and directed by the Emperor’s mind across roughly fifty thousand light years. By its light the Navigators chart a course through the warp; during the Heresy the Ruinstorm blotted it out over half the galaxy.

A psyker who has undergone the Soul Binding ritual to the Emperor: he is blinded, but gains the ability to send telepathic messages through the warp. The astropathic network is the nervous system of the Imperium. The Ruinstorm did not “jam the radio” but burned out and drove mad the living operators; hence the strategic blindness of the east of the galaxy in 007–011.M31 — from the birth of the Storm to its breach at Davin.

Cranial implants of the gladiators of Nuceria, driven into Angron before the Emperor found him and later reproduced on the World Eaters. They grant fury and take away peace: the XII Legion cannot stop. Lorgar uses this pathology as fuel for Angron’s ascension on Nuceria.

The totality of the warp gods, their daemons and mortal cults. In the Imperial propaganda of the Great Crusade Chaos “does not exist”; in fact it is precisely Chaos that seduces Horus, gives Lorgar a pantheon and feeds the Ruinstorm. The four principal Gods — Khorne, Tzeentch, Nurgle, Slaanesh — plus “Chaos Undivided” as worship of the whole.

The set of regulations that Guilliman will write after the Heresy, breaking the Legions up into Chapters of a thousand warriors each. In 005–014.M31 there is as yet no Codex: the Legions are armies of very different sizes, from about ten thousand (the XV by the time of Prospero) to about two hundred and fifty thousand (the XIII). On the map of the Heresy you see precisely a Legion war; the Great Scouring is the transition to the structure familiar from the forty-first millennium.

The council of 001.M31, at which the Emperor forbade the Legions to use battle psykers (Librarians) and in effect condemned Magnus. The Edict of Nikaea is a political compromise: Mortarion (the chief accuser), Russ and Dorn spoke against psionics, the Thousand Sons for. Consequences: Prospero was left without “legal” protection for psionics, and Horus later used the ban to disarm the loyal Librarians before Isstvan.

A mortal elevated by the gods of Chaos into an immortal warp form. In the Heresy this path is taken by Magnus (the oath to Tzeentch on burning Prospero), Fulgrim (Iydris: Perturabo, in a rage, destroys his brother’s mortal shell — and thereby unwittingly completes his apotheosis, Slaanesh), Angron (Lorgar’s ritual on Nuceria, Khorne) and Mortarion (Nurgle, on the way to Terra). Which of them is the “first” is disputed: in the atlas’s chronology Magnus’s oath comes earliest (004.M31), but the atlas places the completeness of his ascension at a later time, and Index Astartes puts Fulgrim’s daemonhood after the Heresy altogether. By the finale Horus is not a classical daemon prince but a vessel of all Four; the exact metaphysics is disputed.

A political and religious officer of the Word Bearers, the heir of the chaplain, preaching the gods of Chaos. Erebus is the archetype; Kor Phaeron stands beside him as the Black Cardinal of the Legion. At Calth the apostles lead not only the assault but also the ritual that swelled the star Veridia. If the map of the XVII Legion shows “preaching”, an apostle and a sacrifice are almost always nearby.

The part of the Machine God’s cult that broke away after the Schism of Mars (005.M31), following Horus and Fabricator General Kelbor-Hal. They embraced warp technologies, daemon-machines and “free” research, forbidden by the Omnissiah of Terra. It is from here, from 005–006.M31 onwards, that the traitors’ supply of weapons, Titans and orbital siege equipment comes.

An armoured combat sarcophagus in which a mortally wounded Space Marine is interred so that he may go on fighting for centuries. In the era of the Heresy the Contemptor class predominated; fallen heroes became tireless machines of war.

The last monumental entrance into the inner Imperial Palace. In the finale of the Siege it is here that Sanguinius holds the line against the Bloodthirster Ka’Bandha and the hordes while the boarding of the Vengeful Spirit is prepared. The fall of the Eternity Gate would have meant the fall of the throne room itself.

The collective name for the Imperium’s mortal armies of the Great Crusade (later the Imperial Army, later still the Astra Militarum). Without them a Legion cannot hold a world. The Heresy splits the Excertus along the same lines as the Astartes: regiments choose Horus or Terra, and in many theatres it is they who hold the line after the Space Marines have gone.

The Imperium’s ultimate sanction: the destruction of all life on a planet by virus bombs, cyclonic torpedoes or orbital fire. In the Heresy both sides employ it; the textbook case is Isstvan III, where Horus scorched his own loyalists. On the atlas an Exterminatus is not a “victory” but an admission that the world has been struck off the logistics for good.

A gigantic permanent warp rift in the Segmentum Obscurus (the galactic north / north-west), born of the fall of an ancient eldar civilisation and the birth of Slaanesh. After the Siege of Terra the surviving traitor Legions retreated here; the Great Scouring stopped at its edge, because real space there no longer holds to the laws of physics.

An ancient throne-machine in the Imperial Palace, through which the Emperor ran the Webway project and held the warp breach. After Magnus’s breach (004.M31) the Throne became prison and life-support system in one: the Emperor could not leave it without bringing Terra down. In the finale of the Siege the dying Emperor is seated upon the Throne; Malcador burns out holding the Throne until that moment.

The loyalist counter-offensive after the death of Horus, approximately 014–021.M31 (the exact bounds are disputed). The traitors are driven towards the Eye of Terror; in parallel Caliban falls, Guilliman writes the Codex, and Dorn goes into the Iron Cage. This is no longer the Heresy as a civil war but a purge, out of which the Imperium of the forty-first millennium will be born.

The civil war of the Imperium, ~005–014.M31, in which nine Legions of the Legiones Astartes and a considerable part of the Mechanicum rose up under the Warmaster Horus Lupercal. The canonical arc on this map runs from the Ullanor Triumph (000.M31) through Isstvan, Calth and Beta-Garmon to the Siege of Terra and onward to the Great Scouring. The dates of individual campaigns within this frame often diverge between the novels and the Black Books.

The single-pilot battle walkers of the Knight Houses: below a Titan, but above any tank. The houses swore allegiance either to Terra (Questor Imperialis) or to Mars (Questor Mechanicus); in the Heresy many split within a single world — the classic example being House Devine on Molech. On the map a knight is a marker of feudal war: a world with a house seldom surrenders without a siege.

The official secular ideology of the Great Crusade: no gods, no spirits, reason and science displacing superstition. It was for preaching against the Truth — for the cult of the Emperor — that Lorgar got Monarchia. The irony of the canon is that the Truth was a lie about the warp, and the forbidden faith of Lectitio Divinitatus became the state religion after the Heresy.

A second Imperium on the eastern fringe of the galaxy, centred on Macragge and Ultramar, founded by Guilliman in 009.M31, when the Ruinstorm cut off the east and there was no word from Terra. It was ruled by a triumvirate of primarchs: Sanguinius as Regent, Guilliman as Lord Warden, the Lion as Lord Protector.

The god of blood, rage and battle. In the Heresy his chosen is Angron: the Butcher’s Nails, the slaughter of the Shadow Crusade and the ritual at Nuceria turn the primarch into a daemon prince of Khorne. After that the World Eaters fight no longer as a Legion but as a ritual: they do not care who the enemy is, so long as blood is spilled.

A secret force assembled by the Regent Malcador after Isstvan III from exemplary warriors of all the Legions — loyalists and traitors alike. Clad in grey-steel armour without markings, except for the seal of the Sigillite, they waged the “Silent War” and became the seed of the Grey Knights and the Inquisition.

A forbidden doctrine that proclaimed the Emperor a god in defiance of the Imperial Truth of secular rationalism. It arose among the Word Bearers (for which Monarchia was razed) and during the Heresy spread among mortal loyalists through the efforts of Euphrati Keeler, becoming the seed of the future Imperial Creed.

The Emperor’s personal guard, the “Ten Thousand” — warriors more perfect than any Space Marine, each created individually. Not subordinate to the primarchs, they lost nine tenths of their number in the War Within the Webway beneath the Palace and held the defence of the Imperial Palace throughout the Siege of Terra.

The “Death’s Heads” — a Titan Legion of Mars, attached to Horus’s 63rd Expeditionary Fleet back in the Great Crusade. On Mars they supported the rebel Fabricator General Kelbor-Hal and became the first Titan Legion to declare for the Warmaster; thereafter they were the backbone of the traitors’ titanomachy up to the Siege of Terra. Their counterweight on the loyalist side is, among others, Legio Ignatum.

The walking god-machines of the Mechanicum — from the scout Warhounds (the lightest class, about 15 m) through the mid-sized Reavers to the Warlords, the main battle Titan of the line, and up to the colossi of the Imperator class. The exact dimensions diverge between sources, so the map operates in classes rather than metres. In the Heresy the Titan Legions split along with Mars; at Beta-Garmon more than a thousand machines came together, and whole Titan Legions were wiped out for good. On the map the presence of a Titan almost always means that the stake is not a city but an entire theatre.

The twenty Space Marine Legions of the Great Crusade — genetically enhanced warriors bred from the genome of the primarchs. Each numbered tens, even hundreds of thousands of fighters; in the Horus Heresy nine Legions went over to the traitors.

A psyker-Astartes who fights within a Legion. Nikaea forbade their open use; some Legions disbanded their Librarius, some hid it. At Isstvan Horus used the edict to disarm the loyal psykers in advance. After the Heresy the Librarians will return under the strict control of the Codex and the oversight of the Inquisition.

A viral Exterminatus agent: it breaks organic matter down into combustible gases, after which a single spark is enough to burn the atmosphere of a world. Used by Horus on Isstvan III against his own loyalists — hence the “Atrocity” and not the “battle”. On the map the life-eater sign means: after this the world is no theatre but a grave, even if the surviving fighters are still fighting on the surface.

The second-largest permanent warp storm of the galaxy — in the Segmentum Ultima, closer to the galactic core. In the era of the Heresy it has little to do with the retreat of the traitors, but on the map it matters as a “hole” in navigation: fleets steer around it, routes break, and piracy and xenos flourish along its edge. Not to be confused with the man-made Ruinstorm of 007.M31.

The technocratic cult of Mars, worshipping the Machine God (the Omnissiah) and supplying the Great Crusade with weapons, machines and the Titan Legions. In 005–006.M31 the Schism of Mars split it: Fabricator General Kelbor-Hal led the Dark Mechanicum to Horus.

A council of four captains attached to Horus — the “sons” of the Warmaster, a balance of temperaments. By 005.M31 it comprises Abaddon, Aximand, Torgaddon and Loken. The split of the Mournival on Isstvan III is a miniature of the split of the entire Legion: Abaddon and Aximand follow Horus, Torgaddon and Loken remain loyalists. Torgaddon is killed by Aximand in a duel; Loken is thought dead, but survives under the rubble and later joins the Knights-Errant under the name “Cerberus”.

Mutant psykers of the ancient Navis Nobilite Houses, whose third “warp eye” allows them to see the light of the Astronomican and to chart a course through the Immaterium. Without them long-range travel is impossible; when the Ruinstorm hid the beacon, the Navigators were all but blind.

The god of disease, decay and the perverted “gift” of immortality. The wound from the anathame at Davin is his trace; the Destroyer Plague on the Death Guard’s road to Terra turns Mortarion’s Legion into a walking epidemic. At the Siege the plague of the Death Guard is as much a siege weapon as Perturabo’s artillery.

The Machine God of the cult of Mars. The Mechanicum identified the Emperor with the Omnissiah in the Treaty of Mars; the Schism of 005.M31 was also theological: Kelbor-Hal rejects this identification and accepts the “true” knowledge of the warp. After the Heresy the loyal branch will become the Adeptus Mechanicus.

A pre-Imperial biotechnical device of xenos (necrons) beneath Mount Pharos on Sotha, drawing its power from empathy. Activated by the loyalist Barabas Dantioch, it replaced the Astronomican that had gone dark and made navigation through the Ruinstorm possible — the technical backbone of the Imperium Secundus.

Twenty superhuman demigods, created by the Emperor in genetic laboratories beneath Terra and scattered across the galaxy by the Ruinous Powers. Each became the genetic father and commander of his own Legion of the Legiones Astartes; two of the twenty were struck from the Imperial records.

The Imperial and theological name for the four gods of Chaos and their combined influence. In the Book of Lorgar, Lorgar calls them the true gods; the Imperial Truth denies their very existence. The Ruinstorm, Davin, Signus, Molech — the points where the Ruinous Powers act as a party to the war, no longer as a metaphor.

A colossal warp storm, devised by Lorgar and called up by the ritual of First Chaplain Erebus at Calth through the killing of the star Veridia. It split the galaxy in two, blinding the Astronomican over the east and cutting the loyalists off from one another, which forced Guilliman to found the Imperium Secundus.

One of the five strategic zones of the Imperial map: Solar (centre), Obscurus (north), Pacificus (west), Tempestus (south), Ultima (east). The headquarters of each is a Segmentum fortress. The Heresy breaks this grid: the Ruinstorm effectively cuts Ultima off from Solar, and orders from Terra do not reach it for years.

The Iron Hands, Salamanders and Raven Guard who survived Isstvan V, plus loyalists from the traitor Legions. They do not restore the front but wage a raiding war: the mixed cells of Shadrak Meduson, the strike cruiser Sisypheum with a crew drawn from all three Legions, the hunt for the traitors’ supply lines. On the map their traces are a dotted line, not an arrow of advance.

An ancient female order of Nulls — bearers of the Pariah gene, immune to psionics and quenching it by their mere presence. Like the Custodians, they answered only to the Emperor; they fought at the Burning of Prospero and held the warp breach beneath the Palace.

The god of excess, perfection and sensory hunger. The blade of the laer and the fall of Fulgrim are the canonical entry of Slaanesh into the Heresy: the blade was taken as early as the Cleansing of Laeran (001.M31, the dating is disputed), long before the open rebellion, and the corruption of the III Legion proceeds from there. By the Siege of Terra the Emperor’s Children are no longer a model formation but an instrument of terror, whose value lies in terror and not in the discipline of the line.

Elite formations of the Excertus Imperialis: cohorts of heavy infantry in sealed, void-adapted armour, often attached to the Legions. On Isstvan, Calth, Tallarn and Beta-Garmon they die in their millions — and on the map it is their presence that makes a battle planetary rather than a purely Astartes duel.

The doctrine of the Luna Wolves and the Sons of Horus: not to stretch the front, but to strike with a mixed detachment precisely at the enemy’s command node and bring a campaign down with a single stab. At Ullanor this brought Horus fame and the title; at Isstvan III the same doctrine was applied against his own sons. When reading the XVI Legion on the map, look not for lines but for points of impact.

Master ordnance officers of the Iron Warriors, in charge of the Legion’s super-heavy siege weaponry. At the Siege of Terra three Stor-Bezashk under Perturabo delivered a strike on the level of a weapon of mass destruction that wiped out the Magnifican, the north-eastern megastructure of the Palace.

A tuft of hair on a shaven head — a cultural marker of the Cthonian officers of the Luna Wolves and the Sons of Horus: Loken, Abaddon, Torgaddon, Aximand. In the novels it is not fashion but a sign of belonging to the strike elite of the XVI, from which came both the loyalist opposition and the future Black Legionaries.

The god of change, intrigue and sorcery. Patron of Magnus and the Thousand Sons: it is his “salvation” that carries the Legion from burning Prospero into the Eye of Terror, to the Planet of the Sorcerers — in exchange for Magnus’s oath. The price will be paid in full later, by the Rubric of Ahriman, after the Heresy. On the map the traces of Tzeentch are not front lines but impossible relocations, deceptive alliances and psychic catastrophes.

The title granted by the Emperor to Horus at Ullanor: supreme commander-in-chief of the Great Crusade after the Emperor’s departure for Terra. Politically this made Horus “first among equals” over the other primarchs and gave him the legitimacy to gather Legions that were not his own. Without this title Isstvan V as an operation would have been impossible.

A different dimension of psychic energy, also called the Immaterium — a seething sea beyond reality, home to the entities of Chaos. Interstellar travel and astropathic communication are possible only through the warp, but passage through it is deadly without the light of the Astronomican.

Semi-secret brotherhoods within the Legions, brought in by the Word Bearers on the model of the Davin cults. Formally, a place where a warrior speaks without rank insignia; in fact, a parallel hierarchy that prepared officers for treason even before Davin. On Isstvan III membership of a lodge often (though not always) correlated with who stayed in orbit and who was sent down to “cleanse” the loyalists.

An extra-dimensional network of tunnels built by an ancient race (the eldar and still older builders), allowing travel without the warp. The Emperor’s secret “Great Work” beneath the Palace was to give humanity a road independent of the warp. Magnus’s breach let the daemons in; the War Within the Webway burned out the Custodians and chained the Emperor to the Throne for the whole of the Heresy.