It is a time of legend. The galaxy is in flames. The Emperor’s glorious vision for humanity is in ruins. His favoured son, Horus, has turned from his father’s light and embraced Chaos. His armies, the mighty and redoubtable Space Marines, are locked in a brutal civil war. Once, these ultimate warriors fought side by side as brothers, protecting the galaxy and bringing mankind back into the Emperor’s light. Now they are divided. Some remain loyal to the Emperor, whilst others have sided with the Warmaster. Pre- eminent amongst them, the leaders of their thousands-strong Legions, are the pri- marchs. Magnificent, superhuman beings, they are the crowning achievement of the Emperor’s genetic science. Thrust into battle against one another, victory is uncertain for either side. Worlds are burning. At Isstvan V, Horus dealt a vicious blow and three loyal Legions were all but destroyed. War was begun, a conflict that will engulf all mankind in fire. Treachery and betrayal have usurped honour and nobility. Assassins lurk in every shadow. Armies are gathering. All must choose a side or die. Horus musters his armada, Terra itself the object of his wrath. Seated upon the Gold- en Throne, the Emperor waits for his wayward son to return. But his true enemy is Chaos, a primordial force that seeks to enslave mankind to its capricious whims. The screams of the innocent, the pleas of the righteous resound to the cruel laughter of Dark Gods. Suffering and damnation await all should the Emperor fail and the war be lost. The end is here. The skies darken, colossal armies gather. For the fate of the Throneworld, for the fate of mankind itself... The Siege of Terra has begun. ‘There are three weapons in the armoury of the victorious. Endurance, Belief and Loyalty.’ – Monito san Vastall, First General-Maximus of the Lucifer Blacks ‘There is no foe so powerful or so innumerable that we cannot overcome them with single- minded determination. Our weapons are simply an extension of our will, and it is our will that shall conquer the galaxy.’ – Warmaster Horus, address to the Ullanor Triumph ‘Faith exists to be tested.’ – Lorgar Urizen, Lectitio Divinitatus DRAMATIS PERSONAE HORUS, Warmaster, Primarch of the XVI Legion, Ascendant Vessel of Chaos The Primarchs PERTURABO, ‘The Lord of Iron’, Primarch of the IV Legion ROGAL DORN, Praetorian of Terra, Primarch of the VII Legion ANGRON, ‘The Red Angel’, Primarch of the XII Legion FULGRIM, ‘The Phoenician’, Primarch of the III Legion MORTARION, ‘The Lord of Death’, Primarch of the XIV Legion JAGHATAI KHAN, ‘The Warhawk’, Primarch of the V Legion SANGUINIUS, Archangel of Baal, Primarch of the IX Legion The IV Legion ‘Iron Warriors’ KYDOMOR FORRIX, ‘The Breaker’, First Captain, Triarch BARBAN FALK, ‘The Warsmith’, Triarch KROEGER, Triarch VULL BRONN, ‘The Stonewrought’, 45th Grand Battalion VOLK-SA’RA’AM, ‘The Obliterator’ GHARAL, Captain BEROSSUS, Captain, Dreadnought The VII Legion ‘Imperial Fists’ SIGISMUND, Lord Castellan, Marshal of the Templars FAFNIR RANN, Lord Seneschal, Captain of the First Assault Cadre HAEGER, Lieutenant-Commander, Castellan of the Lion’s Gate space port ORTOR, Sergeant, First Squad, First Assault Cadre The XIV Legion ‘Death Guard’ TYPHUS, First Captain, Host of the Destroyer Hive The XVI Legion ‘Sons of Horus’ EZEKYLE ABADDON, First Captain The XVII Legion ‘Word Bearers’ ZARDU LAYAK, ‘The Crimson Apostle’, Master of the Unspeaking KULNAR, Slave of the Anakatis Blade HEBEK, Slave of the Anakatis Blade The XII Legion ‘World Eaters’ KHÂRN, Captain, Eighth Assault Company The Dark Mechanicum INAR SATARAEL, Archmagos The Neverborn COR’BAX UTTERBLIGHT, The Life Within Death Imperial Army COLONEL MAIGRAUT, Chief of Staff, Lion’s Gate space port ZENOBI ADEDEJI, Volunteer, Addaba 64th Defence Corps MENBER ADEDEJI, Volunteer, Addaba 64th Defence Corps KETTAI, Volunteer, Addaba 64th Defence Corps YENNU EGWU, Captain, Addaba 64th Defence Corps OKOYE, Lieutenant, Addaba 64th Defence Corps ALEKZANDA, Sergeant, Addaba 64th Defence Corps SELEEN, Volunteer, Addaba 64th Defence Corps SWEETANA, Volunteer, Addaba 64th Defence Corps TEWEDROS, Volunteer, Addaba 64th Defence Corps JAWAAHIR ADUNAY HADINET, Integrity High Officer, Addaba 64th Defence Corps KATSUHIRO, Trooper, Palatine Arc quarantine zone garrison NASHA, Tank commander, Breath of Wrath, Bakk-Makkah First Regiment Imperial Personae MALCADOR, Regent of the Imperium EUPHRATI KEELER, Former Remembrancer KYRIL SINDERMANN, Former Iterator VALDOR, Captain-General of the Legio Custodes AMON TAUROMACHIAN, Custodian OLIVIER MUIŽNIEKS, Head of the Lightbearers MANISH DHAUBANJAR, Hauler operator DAXA DHAUBANJAR, Hauler operator Himalazia, undisclosed location, date unknown The smog of hundreds of engines blackened the sky, adding to the gloom of the filth-choked heavens. The thunder of tanks and transports, some the siZe of city blocks, created a deafening wave of sound that reverberated from the mountainsides, an assault on ears already numbed by the winds of the high HimalaZia. The growl of machine voices all but drowned out human shouts, even those amplified by voxmitters. Electronic clarions howled into the whirl of noise, sounding the advance or stand-to, their modulated calls overlapping. Everything was sudden movement, dust billowing from treads and boots alike. ‘This is it.’ General-Captain Egwu did not raise her voice, but her words were carried by the tongues of those under her command. ‘Everyone stand ready.’ Beside her, Zenobi Adedeji fidgeted with the cover of the banner she carried, eyes flicking be- tween her company commander and the scene of organised bedlam being enacted around the troopers from Addaba Hive. ‘Everything we have done, the oaths we have sworn, the hardships we have endured, has led to this moment.’ Now Egwu shouted, not simply to be heard, but filled with passion. Her re- maining eye stared wide amongst the burn scars that covered most of her face, fresh tissue pink against her dark skin. ‘Now is the time we strike at the enemy! Our families laboured and died to deliver us to this place. Our courage and determination have carried us this far. We may not live beyond this day, but our deeds will!’ ‘Now?’ asked Zenobi, her voice quavering with emotion, a shaking hand reaching towards the cover of the standard. ‘Yes,’ said the general-captain. ‘Now.’ The Lord of Iron Farewells An honour bestowed The Iron Blood, Terran near orbit, seventy hours before assault Patches of static in the holo-display vexed Perturabo, causing him pain in a way that a wound to his flesh could not. Every blur marring the projected image was a failure of surveyors, each a gap in his knowledge. His only companions were the six automatons of his Iron Circle, stationed at regular intervals around the periphery of the octagonal chamber. They stood with their shields raised, mauls dor- mant, the only movement that of their ocular lenses, which whirred and clicked as they followed the pacing of their creator. ‘I could extrapolate the defences hidden from me,’ Perturabo thought aloud to his bodyguard. Their unquestioning silence was a welcome break from the ceaseless doubts and queries that spilled from his subordinates of late. ‘I have perfect recollection of other works raised by Dorn, and by patterning those memories with what is shown here I can fill the gaps to a high degree of accuracy.’ He stared at a glimmering hololith that filled most of his planning chamber aboard the Iron Blood, as though force of will could make it offer up its secrets. ‘Extrapolation is not fact,’ he growled. ‘There is too much at stake for assumption, no matter how well informed.’ His mind, his military genius, was the key Horus needed to unlock the palace of his father, but it needed data like an army needed supplies. He stepped into the display, his massive suit of armour hissing and wheeZing. Its shadow oblit- erated whole sectors of the Sanctum Imperialis as he strode to examine one area in particular. He crouched, coming eye to eye with a fictional defender standing on the Ultimate Wall. The yellow of Dorn’s Legion was spread everywhere, though it was concentrated around the north-east and south-west. The red of the Blood Angels was strongest to the south-east, where Mortarion’s Death Guard had launched a damaging but ultimately unsuccessful assault near the Helios Gate. The Khan’s White Scars were harder to place. They had sallied forth against Mortarion in sup- port of Sanguinius, but had since been seen in several other battles to the north and west of that attack. The precise whereabouts of the primarchs themselves was a factor to be considered, but impossible to ascertain with any degree of timeliness or certainty. Raising the fingers of his left hand, he gestured and the display rotated around him, placing him behind the wall so that he was looking out across the Katabatic Plains surrounding the Palace. The Warmaster’s forces were rendered in a more abstract sense; series of runes, numbers and sigils denoting troop type, strength, current morale estimates, longevity of engagement, and half a dozen other factors. And there were more features, sketched with a nomenclature he was still creating. These were the forces of the warp, whose powers he had only just started to investigate. Daemons. Possessed legionaries. Word Bearers and Thousand Sons sorcerers. And his brothers. Swirls of arcane conjunctions between the real and the imaginary, with a foot in the world of the mortal and immortal alike. Angron, so determined to prove himself, unable to hold his wrath, was still trying the defences at Helios. Mortarion had not personally attempt- ed to breach the Emperor’s shield yet, and at the command of Horus was redirecting efforts to the south-west, attacking a twenty-kilometre stretch of wall near to the bastion of the Saturnine Gate.