{{otheruses|USE=[[Horus Heresy]] Battle|OTHERUSE=battle at the end of [[M41]]|OTHERPAGE=Battle of Lion's Gate}}

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|Image caption= The Emperor of Mankind battles Warmaster Horus Lupercal aboard the ''Vengeful Spirit''.

|Conflict = [[Horus Heresy]]

|Location = [[Terra]]

|Outcome = Pyrrhic Loyalist victory

|Combatant2 = [[File:Chaos.png|30px]] Forces of [[Chaos]]

[[File:IF Icon.png|20px]] [[Rogal Dorn]]<br>

[[File:WS Icon.png|20px]] [[Jaghatai Khan]] (WIA)<br>

[[File:SAL Icon.png|20px]] [[Vulkan]] (Hidden){{Fn|14}}<br>

[[File:IF Icon.png|20px]] [[Kestros|Archamus]]{{Fn|13d}}<br>

[[File:IF Icon.png|20px]] [[Fafnir Rann]]{{Fn|10j}}<br>

[[File:IF Icon.png|20px]] [[Maximus Thane]]{{Fn|8}}<br>

[[File:IF Icon.png|20px]] [[Fisk Halen]]{{Fn|13a}}<br>

[[File:IF Icon.png|20px]] [[Sevastin Haeger]]{{Fn|10j}}<br>

[[File:BA Icon.png|20px]] [[Raldoron]]<br>

[[File:BA Icon.png|20px]] [[Azkaellon]]<br>

[[File:BA Icon.png|20px]] [[Nassir Amit]]<br>

[[File:BA Icon.png|20px]] [[Zephon (Blood Angels)|Zephon]]<br>

[[File:BA Icon.png|20px]] [[Anzarael]]<br>

[[File:BA Icon.png|20px]] [[Khoradal Furio]]<br>

[[File:BA Icon.png|20px]] [[Satel Aimery]]<br>

[[File:BA Icon.png|20px]] [[Emhon Lux]] (WIA)<br>

[[File:WS Icon.png|20px]] [[Ganzorig Noyan-Khan]]<br>

[[File:WS Icon.png|20px]] [[Shiban Khan]]{{Fn|13g}}<br>

[[File:WS Icon.png|20px]] [[Jangsai Khan]]{{Fn|13g}}<br>

[[File:WS Icon.png|20px]] [[Namahi]]<br>

[[File:DA Icon.png|20px]] [[Corswain]]{{Fn|13g}}<br>

[[File:SAL Icon.png|20px]] [[Atok Abidemi]]{{Fn|14}}<br>

[[File:SAL Icon.png|20px]] [[Igen Gargo]]{{Fn|14}}<br>

[[File:Custode Icon.png|20px]] [[Amon Tauromachian]]{{Fn|10j}}<br>

[[File:Machina Opus.png|20px]] [[Zagreus Kane]]<br>

[[File:Imperial Army Symbol.jpg|20px]] [[Adreen]]<br>

[[File:Imperial Army Symbol.jpg|20px]] [[Ilya Ravallion]]<br>

[[File:Imperial Army Symbol.jpg|20px]] [[Sandrine Icaro]]<br>

[[File:Imperial Army Symbol.jpg|20px]] [[Aldana Agathe]]{{Fn|13}}<br>

[[File:Imperial Army Symbol.jpg|20px]] [[Clement Brohn]]<br>

[[File:Custode Icon.png|20px]] [[Diocletian Coros]]<br>

[[File:IW Icon.png|20px]] [[Perturabo]] (AWOL)<br>

[[File:WE Icon.png|20px]] [[Angron]] (Banished)<br>

[[File:DM Icon.png|20px]] [[Kelbor-Hal]]<br>

[[File:SOH icon.png|20px]] [[Ezekyle Abaddon]]<br>

[[File:SOH icon.png|20px]] [[Falkus Kibre]] (KIA?){{Fn|13f}}<br>

[[File:SOH icon.png|20px]] [[Lev Goshen]] (MIA){{Fn|13f}}<br>

[[File:SOH icon.png|20px]] [[Azelas Baraxa]]<br>

[[File:SOH icon.png|20px]] [[Xhofar Beruddin]]<br>

[[File:SOH icon.png|20px]] [[Malabreux]]<br>

[[File:SOH icon.png|20px]] [[Hellas Sycar]]<br>

[[File:SOH icon.png|20px]] [[Taras Balt]]<br>

[[File:SOH icon.png|20px]] [[Vorus Ikari]]<br>

[[File:SOH icon.png|20px]] [[Kalintus]]<br>

[[File:SOH icon.png|20px]] [[Zistrion]]<br>

[[File:SOH icon.png|20px]] [[Ekron Fal]]<br>

[[File:WB Icon.png|20px]] [[Erebus]]<br>

[[File:DG Icon.png|20px]] [[Typhus]]<br>

[[File:DG Icon.png|20px]] [[Caipha Morarg]]<br>

[[File:DG Icon.png|20px]] [[Zadal Crosius]]<br>

[[File:WE Icon.png|20px]] [[Khârn]] (KIA)<br>

[[File:WE Icon.png|20px]] [[Shâhka Bloodless|Shâhka]]{{Fn|23}}<br>

[[File:IW Icon.png|20px]] [[Kroeger]] (AWOL){{Fn|10j}}<br>

[[File:IW Icon.png|20px]] [[Barban Falk]] (AWOL){{Fn|10j}}<br>

[[File:NL Icon.png|20px]] [[Gendor Skraivok]] (MIA)<br>

[[File:NL Icon.png|20px]] [[Krostovok]]<br>

}}

==Overview==

===Prelude===

*{{Main|Solar War}}

Facing them were the armies of [[Chaos]] under [[Warmaster]] [[Horus]] which included nine Legions of [[Chaos Space Marines]], traitorous forces of the [[Imperial Army]], [[Daemon|Daemonic hordes]], and the [[Titan Legion]]s of the [[Dark Mechanicum]].{{Fn|1a}} [[Mars]], the capital of the [[Adeptus Mechanicus]], had recently [[Schism of Mars|fallen]] to the traitor forces. The situation had become disastrous for the [[Imperium]] and the forces of the [[Emperor]]. Horus, sensing that he could decisively end the conflict and overthrow the Emperor once and for all, began to move on Terra. [[Rogal Dorn]], of the [[Imperial Fists]], was given overall command of the defenses of humanity's homeworld while the Emperor himself was busy with his own secret project, the [[Golden Throne]].{{Fn|1a}} In this endeavor, the Primarch was assisted by hundreds of specialists including: '''Fourth Master Tacticae Terrestria''' [[Julius Gundelfo]], '''Tacticae''' [[Osaka]], [[Montesere]] and [[Brinlaw]], '''Data-Adjudicator''' [[Perez Grist]], [[Imperial Army]] [[Colonel]] [[Lin-Hu Kway]], '''Junior Administrar Patris''' [[Sator Omes]], '''Cogitation Overseer''' [[Arnolf Van Halmere]], and '''Rubricator Senioris''' [[Hyton Ki]].{{Fn|24r}}

===The Storm Breaks===

On the thirteenth day of Secundus, the bombardment of Terra began. From orbit, Horus' ships laid down an unrelenting barrage of missiles and energy beams. The first shell targeted the [[Sanctum Imperialis]], the Emperor's personal quarters, for symbolic reasons, though it did no damage and was quickly intercepted by many point defense systems. A vicious exchange of fire took place as the massive array of anti-ship gun batteries on Terra opened up on the traitor ships. Losses were incurred by both sides, but the traitor fleet in particular took heavy losses in space but endured through sheer weight of numbers.{{Fn|9a}} Horus' ultimate objective was the [[Imperial Palace]], seat of the Emperor himself. The orbital bombardment was some of the most intense ever witnessed and shook even the courageous and battle-hardened loyalists [[Space Marines]].{{Fn|1b}} However damage to the actual Palace itself was minimal due to a sophisticated multi-layered and self-repairing [[Void Shield]] system known as '''The Aegis''' as well as the fact that Terra's last orbital plate was placed over the Palace to serve as a shield and gun platform. However, due to a reactor flaw in one of the Aegis' reactors, a small weakness appeared in the Palace network centered around a Bastion outside the Helios Gate.{{Fn|9a}} Inside the depths of the Palace itself, the Emperor, attempting to keep the [[Golden Throne]] under control, could only brood over the desperate events occurring far above.{{Fn|1b}}

The bombardment continued for days as [[Perturabo]] probed for weaknesses in the Aegis, discovering the flaw around Bastion-16. The Aegis around this area was weakened enough to allow for slow-moving aircraft to penetrate. Despite the ragings of [[Angron]] and the boredom of [[Fulgrim]], Horus would not launch an all-out attack yet. The Emperor's might not only prevented [[Daemon]]s from manifesting on Terra, but also threatened to destroy the [[Daemon Primarch]]'s should they set foot upon its soil. [[Magnus]] and [[Zardu Layak]] surmised a ritual to eliminate the Emperor's barrier by spilling enough blood across Terra. Horus began to increasingly spend his time comatose, his spirit inside the Warp searching for lore as well as weakening the Emperor's spirit,{{Fn|9b}} eventually designating [[First Captain]] [[Ezekyle Abaddon]] as his proxy.{{Fn|9d}} After 12 days the bombardments continued, but were matched with the first ground assaults. Thousands of traitor vessels crashed into Terra's surface. Many were destroyed by the Palace defenses, but many more landed and unleashed endless hordes of Traitor [[Imperial Army]], [[Beastmen]], [[Cultist]]s, and [[Mutant]]s. These were largely distractionary measures to support the traitors' true objectives as they ravaged the planet, as well as support the traitor aerial attacks on the Palace's anti-ship guns and void shield generators. The loyalists responded with their own aerial defenses, and massive dogfights erupted over the Palace as the conscripts outermost trenches around the walls held against the attacks by the [[Lost and the Damned]]. While the Palace held, elsewhere across Terra major population centers fell such as Lundun, Noy Zaylant Hive, Neork, and Braslya.{{Fn|9l}}

[[Image:PalaceMapHH.jpg|thumb|right|250px|The Dark Mechanicum siege camps around the Imperial Palace]]

The pattern of orbital attack, landings by traitor rabble, and aerial assault repeated itself for weeks before the [[Death Guard]] fleet under the now-corrupted [[Mortarion]] arrived at Terra. True to his earlier word to let Mortarion's legion be the first to set foot upon Terra, Horus prepared to use the Death Guard in the first Astartes-led assaults on the Palace.{{Fn|9d}} This caused Angron to rage, and to prevent him from destroying his own flagship ''[[The Conqueror]]'' he was teleported by [[World Eaters]] 8th Company [[Kharn]] into the ever-shifting labyrinth originally built for [[Vulkan]] aboard the [[Night Lords]] flagship ''[[Nightfall]]''.{{Fn|9f}} On the seventh of Quartus the first Death Guard [[Drop Pod]]s landed on Terra's soil as the [[Nine Disciples]] of [[Kelbor-Hal]] each beached one of their [[Ark Mechanicus]]-class [[Battleship]]s around the Palace. The Void Shields and bulk of the Ark Mechanicus vessels allowed for the traitors to establish their first real footholds around the Palace, and as the Death Guard unleashed gas and plagues upon the trenches around the walls the [[Dark Mechanicum]] set about their work of constructing siege engines.{{Fn|9e}} The Death Guard assault on the outermost trenches around the Palace was about to break the Imperial Army defenders until [[Jaghatai Khan]], defying Dorn's orders to remain in the palace, led a [[Jetbike]] charge by the [[White Scars]]. The Scars pushed past the traitor frontline into their siege camps before the Khan was finally forced from his Jetbike. Jaghatai slew dozens of Death Guard until he was wounded by a [[Warp]]-tainted poisoned blade. Ultimately [[Sanguinius]] had to sortie out of the Palace with his [[Sanguinary Guard]] to rescue Jaghatai, who recovered from his Warp sickness as soon as he began to move closer to the Sanctum Imperialis and the psychic might of the Emperor. The Khan's move was not reckless however, he also gathered valuable intelligence on the siege engines the traitors were constructing.{{Fn|9g}} Meanwhile aboard the ''[[Vengeful Spirit]]'', Horus finally allowed [[Perturabo]] to begin his preparations to clear landing zones around the Palace for their [[Titan]]s.{{Fn|9h}}

On the Fifteenth of Quartus, the traitors initiated their dual plan to break The Aegis and allow for the manifestation of Daemons upon Terra. A giant projected face of [[Zardu Layak]] appeared on an island of bones which descended from the sky, urging the commoners of Terra to rise up against the Emperor and ensuring them that if they turned to Horus now they would be spared. The Palace guns could not silence the corporeal island, and after his speech concluded it began to rain blood. The blood signaled that the traitors had finally undertaken their ritual to weaken the Emperor's psychic barrier, and the Mechanicum released their [[Daemon Engine]]s. Eight "Warp-Bane" guns constructed near the sites of the beached ''Ark Mechanicus'' vessels opened up on the Aegis Shield around the Palace, sapping it of its energies as the Death Guard deployed massive [[Nurgle Plague Tower|Towers of Nurgle]] at the walls. As the Aegis gave way the traitor bombardment finally was able to hit the Palace defenses directly, causing massive devastation and allowing for a [[Night Lords]] [[Chaos Raptor|Raptor]] assault on the Eternity Wall. The outermost trenches around the Palace Walls were now untenable, but Sanguinius opened up the Helios Gate and led a massive counterattack by the Blood Angels and Imperial Fists as well as Titans of the [[Legio Solaria]]. Sanguinius knew victory was impossible, but had his Astartes buy enough time to allow for the Imperial Army conscripts to make it inside the walls and allow for Titans to destroy the incoming Towers of Nurgle.{{Fn|9i}} On top of the Eternity Wall itself, Blood Angels First Captain [[Raldoron]] bested the acting Night Lords commander [[Gendor Skraivok]] and threw him from the Walls.{{Fn|9j}} It was in this maelstrom of destruction that [[Angron]] himself fell from the sky, having been released from the bowels of the ''[[Nightfall]]''. After massacring his way through friend and foe alike to the Eternity Wall Angron bellowed a challenge to Sanguinius, who saluted his fallen brother and stated that while they would battle one day, today was not that day. Angron raged, but could not proceed any further due to the lingering effects of the Emperor.{{Fn|9k}}

===Battle for Lion's Gate Spaceport===

Though the rest of Terra was in chaos or in Traitor hands, the Palace stood firm. All traitor attacks against the walls failed to achieve a breakthrough, and the Emperor's psychic shield endured strong enough to keep the Daemon Primarch's from the Palace. In order to further the weakened Emperor's barrier, both Horus and [[Magnus]] launched psychic attacks against Him. Magnus utilized the gestalt [[Daemon]] [[Shai-Tan]] in the attacks.{{Fn|11}} At Horus' command Mortarion attacked near the Saturnine Gate turning the previously lavish Palatine Arc into an infected quagmire nicknamed Poxville. Angron fruitlessly rampaged outside of the Helios Gate, and Fulgrim's degenerate hordes launched raids to both the west and north. The Emperor's Children were already beginning to leave the frontline, instead taking prisoners for their own perverse reasons. Of Magnus there was no sign, and not even Malcador could ascertain his true intentions. In this stalemate, Horus placed [[Perturabo]] in charge of achieving a major breakthrough. Perturabo surmised that the [[Lion's Gate Spaceport]] was both the weakest and strongest points in the Palace's defenses. Taking it would allow the traitors to land badly needed [[Titan]]s and give the traitors access to both the Inner and Outer Palaces. At the same time however, it was one of the most heavily defended bastions. This did not deter Perturabo, and he shocked his [[First Captain]] [[Forrix]] by placing [[Kroeger]] in charge of the assault on the Spaceport. Perturabo hoped that Koreger's bluntness would shock Dorn, who had planned for a more sophisticated attack.{{Fn|10a}}

Dorn agreed to provide Rann with reinforcements under [[Sigismund]] to prevent a total traitor victory at the Spaceport. During the defense Rann was wounded by Kroeger but saved by Sigismund, who led a vicious counterattack.{{Fn|10f}} It soon became apparent that the Iron Warriors attempt to seize the bridges had been simply a feint. Perturabo used Forrix's men to shield his true intentions, docking the ''[[Iron Blood]]'' with the Space Port's space elevator facilities and unloading waves of new reinforcements. The defection of the [[Addaba Free Corps]] prevented Dorn from sending reinforcements and the situation collapsed for the loyalists. In the ensuing brawl Sigismund battled Kharn, but while the [[First Captain]] was the superior warrior the World Eater's Captain was now infused with [[Khornate]] strength. Sigismund was bested, but saved by the appearance of Rogal Dorn himself who slapped away Kharn like an insect. Abaddon refused to allow Kharn to die and led a counterattack to save the World Eater, forcing Layak to intervene in order to save the future [[Warmaster]] of Chaos from the Primarch's wrath.{{Fn|10g}} Layak held off Dorn for a time with his sorcerous power, but was eventually slain. However, as he died he opened a portal to the [[Warp]] which allowed the first [[Daemon]]'s to manifest on Terra. With the situation now hopeless, Dorn ordered a withdrawal as Perturabo himself landed in the Spaceport. The two brothers came face to face, but both refused to waste their time and resources engaging one another in a fruitless duel. Perturabo had taken the First Wall, but there were still many more left to capture before the Sanctum Imperialis. Perturabo was undeterred as he oversaw the landing of the first Traitor Titans from the [[Legio Fureans]] upon Terra.{{Fn|10h}}

At Gorgon Bar, [[Blood Angels]] Primarch [[Sanguinius]] and [[Imperial Fists]] Captain [[Fafnir Rann]] oversaw the defenses against a large [[Iron Warriors]]-led assault under [[Yzar Chroniates]], [[Ormon Gundar]], and [[Bogdan Mortel]].{{Fn|13b}} During the battle, Sanguinius destroyed a [[Warlord Titan]] of the [[Legio Vulpa]] by boarding its head and impaling it with the [[Spear of Telesto]]. Such was the spectacle that three accompanying traitor [[Warhound Titan]]s fled from Sanguinius' sight.{{Fn|13a}} Thanks to the inspiration provided by Sanguinius, the traitor assault at Gorgon Bar was broken when the defenders drove the Iron Warriors from the towers of the Fourth Circuit Wall.{{Fn|13b}} At the Colossi Gate, the defenders were led by Primarch [[Jaghatai Khan]], Blood Angels [[First Captain]] [[Raldoron]], [[Marshal]] [[Aldana Agathe]], and [[Custodes]] [[Captain-General]] [[Constantin Valdor]]. Not wanting to wage a purely defensive war and wishing to eventually retake the Lion's Gate Spaceport, Jaghatai Khan led a 300-strong [[Jetbike]] charge from the Colossi Gate that devastated [[Death Guard]]-led forces until at the last moment the White Scars withdrew back to their own lines.{{Fn|13c}} [[Magnus]] and [[Ahriman]] along with a cabal of [[Sorcerers]] from the [[Order of Ruin]] subsequently launched a psychic assault on the defenders, sapping their will to fight and summoning vast amounts of [[Daemon]]s including eight gigantic [[Warhound Titan]]-sized monsters{{Fn|13f}}. However thanks to the defensive storms erected by Jaghatai Khan's [[Stormseer]]'s led by [[Naranbaatar]], the loyalists were able to hold the line.{{Fn|13d}}

Despite the decisive victory at the Saturnine Gate and the defensive successes in holding Gorgon Bar and Colossi, just as Dorn predicted the Eternity Wall Spaceport was doomed. Defenders in the area were led by Imperial Fists Captain [[Camba Diaz]], [[White Scars]] Captain [[Shiban Khan]], [[General|High Primary Solar General]] [[Saul Niborran]], and [[Sisters of Silence]] Commander [[Jenetia Krole]]. The commanders knew that Dorn had no intent of reinforcing them, but not wishing to abandon their doomed troops did not evacuate. Camba Diaz died slaying scores of traitors on the Pons Solar bridge, refusing to take a step back.{{Fn|13f}} Shortly after [[Angron]] himself arrived, and in a moment of clarity requested the surrender of Space Port. Niborran and his [[Imperial Army]] troopers responded by blasting Angron to pieces with the Port's gun batteries, though the traitor Primarch quickly regenerated.{{Fn|13g}} Niborran and his men alongside Krole all fought to the death against a savage [[World Eaters]] assault led by Angron, [[Kharn]], and [[Khornate]] [[Titan]]s. Shiban Khan was thought slain in a shuttle crash while trying to help the last Imperial Army troopers under his command evacuate. Meanwhile at the edge of the [[Sol System]], a contingent of 10,000 [[Dark Angels]] under Captain-Paladin [[Corswain]] arrived to help defend Terra.{{Fn|13e}}

===Magnus' Infiltration===

===The Palace Besieged===

[[Image:WarhawkNoText.jpg|thumb|right|220px|Jaghatai Khan confronts Mortarion at the Lion's Gate Spaceport{{Fn|20g}}]]

The grim outlook of the chance for victory was not shared by the White Scars and their Primarch, Jaghatai Khan, who continued to talk of life after they had won the battle.{{Fn|20a}} Not content to simply hide behind walls, the Khan at last decided at this desperate final hour to make his move. He became committed to retaking the [[Lion's Gate Spaceport]], which if captured would allow Guilliman's coming reinforcements to quickly land on Terra as well as slow the flow of traitor forces. Overworked and exhausted and knowing he could not control his brother, Rogal Dorn did not try to stop the Khan. Facing the White Scars were the bulk of the Death Guard under Mortarion, who had taken up Lion's Gate Spaceort as his new headquarters since the departure of Perturabo.{{Fn|20b}}

As loyalist casualties mounted, the Khan was able to fight his way into the heart of the Spaceport and confront Mortarion himself. The old enemies exchanged few words before engaging in a final duel. Faced with Mortarion's new Daemonic endurance and strength, the Khan was brutally beaten down and nearly defenseless. However he was able to find a weakness in the Death Lord with his pride. Jaghatai Khan scolded Mortarion for being weak and giving into the powers of the Warp, while he himself had resisted the temptations of Chaos and remained true to the Emperor. Mortarion flew into a rage, which the Khan took advantage of to launch a second wave of dizzying attacks that overwhelmed the Primarch. In the end the badly wounded Jaghatai Khan was impaled on the blade of Mortarion's scythe, but simply pulled his body along its length to get face-to-face with the Death Guard Primarch. The loyalist Primarch decapitated Mortarion, who was banished into the Warp in a massive explosion similar to that of a [[Vortex Weapon]]. Later, the Khan's badly wounded body was discovered by [[Ilya Ravallion]] and [[Jangsai Khan]].{{Fn|20e}}

As a vast traitor horde of traitor Astartes, Imperial Army, [[Beastmen]], Mutants, Daemons, Titans, and other horrors massed on the horizon, only some 70,000 defenders mustered on the Delphic Battlement before the processional to the Eternity Gate. These were mainly Blood Angels and Imperial Army, but Imperial Fists, White Scars, [[Legio Ignatum]], and Mechanicum loyalists were also represented. [[Corswain]] offered to send his own forces defending the [[Astronomican]] to aid the defenders, but Sanguinius declined their offer, due to the vital nature of the Dark Angels Paladin's mission.{{Fn|22a}}

The battle that followed was immense. The traitor horde surged forward as the guns of the Delphic Battlements opened up. The initial waves were decimated, but through weight of numbers they began to reach the walls. A Khornate [[Warlord Titan]] docked with the Delphic wall, vomiting forward World Eaters from its mutated mouth. Chaos erupted in short order as the battle turned into a savage melee. Into this strode the [[Bloodthirster]] [[Ka'Bandha]], who had been bested by Sanguinius during the [[Signus Campaign]]. Vowing to reap 500 Blood Angels in the presence of their Primarch, the Daemon nearly succeeded before Sanguinius intervened. The two had a dramatic airborne battle that ended when Sanguinius broke the Daemons back with the hilt of his sword. Ka'Bandha plummeted to the earth, consumed by lesser Daemons taking advantage of his weakness.{{Fn|22e}}

Just moments after the battle of the Eternity Gate, [[Shiban Khan]] and his White Scars managed to reactivate the anti-orbital defenses of the [[Lion's Gate Spaceport]]. The traitor armada, hanging in low-orbit, was subjected to a vicious ground-to-orbit bombardment. Word reached the Sol System that [[Roboute Guilliman]] was just one week away, with [[Leman Russ (Primarch)|Leman Russ]], [[Corax]], and [[Lion El'Jonson]] not far behind.{{Fn|22f}}

{{QuoteBox

It was at this moment that Horus finally emerged from [[Lupercal's Court]] for the first time since the Siege began, apparently in a half-lucid stupor and imagining himself back on the [[Great Crusade]]. Journeying to the bridge of the ''Vengeful Spirit'', he addressed his equerry [[Kenor Argonis]] as [[Maloghurst]], saw long-dead [[Zardu Layak]] at his side, and stated he would finally finish the war. To the shock of all present, Horus stated that he had apparently lowered the ''Vengeful Spirit's'' [[Void Shield]]s, inviting the Emperor himself to [[Teleport]] aboard his flagship. This would allow Horus to slay the Emperor before reinforcements under Guilliman could arrive, which were mere hours away. With their Emperor dead, Guilliman's incoming fleet would lose heart and scatter before the forces of the Warmaster.{{Fn|24e}} However, Guilliman's fleet was still having difficulty finding Terra without the Astronomican, which [[Corswain]] and his Dark Angels sought to reactivate. To thwart the Dark Angels, [[Typhus]] led a massive Death Guard assault upon the [[Forbidden Fortress|Hollow Mountain]].{{Fn|24j}}

While the Emperor led the assault on the ''Vengeful Spirit'', [[Archamus II|Archamus]] was placed in command of the reamining loyalist forces on Terra. Meanwhile at the [[Astronomican]], [[Corswain]] and [[Zahariel|The Lord Cypher]] waged a battle against a [[Death Guard]] assault led by [[Typhus]], who was attempting to stop the reactivation of the Astronomican. If the traitors succeeded, Guilliman's armada would have no way of reaching Terra in time.{{Fn|24j}} For the traitors part, upon discovering their flagships shields were down, Abaddon abandoned the war on the surface along with the last few remaining sane Sons of Horus officers to rush to his fathers side.{{Fn|24p}}

====Operation Anabasis====

[[Image:HorusvSang.jpg|thumb|right|350px|Horus faces Sanguinius{{Fn|25}}]]

Still preparing to face his father, Horus deliberately let [[Sanguinius]] reach him within the heavily mutated [[Lupercal's Court]]. Planning to turn Sanguinius to Chaos so that they may confront their father together, Horus was genuinely disappointed when his brother refused his offer to join him in ascendency.{{Fn|26c}} Instead, the already heavily injured Sanguinius attacked Horus with all his might, displaying ferocious combat ability. Horus still held back his true power, engaging in a purely martial battle with Sanguinius in hopes of breaking him down so he may accept the powers of the Warp. However Sanguinius fought so stubbornly and viciously that Horus grew frustrated and even took several wounds.{{Fn|26d}} In the end, Horus was forced to change his plans when he detected that the Emperor was incoming towards his location. Horus finally decided to kill Sanguinius and unleashed his full power, reaching into the 8th dimension to grab Sanguinius and slam him to the ground mid-flight. Horus proceeded to batter his brother with ''[[Worldbreaker]]'' and impaled him several times with his [[Talon of Horus|Talon]] before the skull of [[Ferrus Manus]]. Horus let out a disappointed sigh as his brother died and his body was strung up by Daemons.{{Fn|26e}}

During all this, the battle still raged across the ''Vengeful Spirit'' and on Terra. The [[Blood Angels]] had been rendered insane with the [[Black Rage]] upon sensing the death of their Primarch and experiencing visions of his demise. They soon struck out a both loyalist and traitor, ravaging all in their path. [[Typhus]] led a final push against the [[Astronomican]], coming into conflict with not only Corswain, [[Zahariel]], and his [[Dark Angels]] but also [[Sigismund]], [[Euphrati Keeler]], and millions of surviving Terran refugees. Abaddon and [[Erebus]] led an offensive against Valdor, Dorn, and the surviving Custodes as both sides came under attack from the frenzied Blood Angels under the now-berserk [[Raldoron]].{{Fn|27c}} Thanks to the Warp powers of [[Erebus]], Abaddon and his [[Justaerin]] were able to badly injure Valdor but he and Dorn were able to escape towards the storm of the Emperor and Horus' battle. However at the Astronomican Keeler and the Dark Angels Librarians were able to utilize a speech being broadcast by [[Actae]] that "The Emperor Must Live" to inspire the throngs of millions. The Death Guard and even Typhus himself were driven back as countless of faithful Terrans sacrificed their souls to the Astronomican to reactivate it.{{Fn|27k}} With the Astronomican lit, Guilliman's reinforcement fleet of over 3,200 capital ships finally had the precise location of Terra and were only scant hours away.{{Fn|27d}} Inside the [[Sanctum Imperialis]], Vulkan prepared to activate the [[Talisman of Seven Hammers]] upon hearing traitor forces pounding on the other side of the door into the Throneroom but was convinced to back down upon hearing Actae's message.{{Fn|27d}}

{{QuoteBox

|quote = '''''By the command of the Praetorian, take up your weapons and advance. The Emperor stands alone, at the hour of greatest peril. Take up your weapons and come to His aid. Protect Him as He protects you. You are the shield of humanity! Rise together and stand as one. Stand at His side now, or all is lost. Terra must endure. The Imperium must stand. Horus Lupercal must fall. The Emperor must live.''''' ~ [[Actae]]'s psychic broadcast across Terra.{{Fn|27k}}

====Lupercal's Court====

When the Emperor, accompanied by [[Caecaltus Dusk]], [[Garviel Loken]], and [[Leetu]] finally reached [[Lupercal's Court]] and found Sanguinius' mauled strung up corpse, the Master of Mankind showed no visible emotion. He simply ordered Sanguinius' corpse be taken down then ignored Lupercal's taunts and proclamations of supremacy, instead addressing the Gods of Chaos observing the battle directly and ordering they stand down. The Emperor stated that the Gods had killed his son, which Horus soon came to understand was a reference to himself as well and not just Sanguinius. Frustrated at being ignored, Horus shot a blast of lightning from his talon and the great duel to decide the fate of humanity finally began. Loken, Leetu, and Caecaltus were quickly thrown aside by the immense power being released.{{Fn|27a}}

The ensuing titanic battle was fought across both the material and immaterial, across time and space and several dimensions simultaneously as the Chaos Gods watched on with glee and excitement. Fully empowered by The Four, Horus was able to match and then surpass the Emperor's own psychic might. What began as a physical contest of sword and maul escalated into a clash across time as they found themselves assailing one another on [[Cthonia]], ancient [[Terra]], [[Ullanor]], [[Gorro]], and even future [[Cadia]]. Horus and the Emperor began to attack one another in their own memories, and finally the battle manifested as a card game with the [[Imperial Tarot]]. Horus utilized his own deck he had been preparing for this, with cards whose creation was aided by the Chaos Gods. At the end of the duel the Emperor played his ultimate card, ''Death'', but Horus countered with ''The Despoiler''. The Emperor was defeated in the metaphysical, and in the material realm he was finally overwhelmed by Horus' barrage of attacks and collapsed.{{Fn|27b}}

[[Image:HorusvsEmp3.jpg|thumb|right|300px|Horus and the Emperor battle{{Fn|25}}]]

It was then that [[Ollanius Persson]] arrived in Lupercal's Court, teleported there alongside [[John Grammaticus]] by [[Actae]]. John used a single line of [[Enuncia]] to briefly blow back the monstrous Warmaster as Ollanius tried to wake the Emperor and give him the [[Athame]] blade they had recovered. John was forced to flee but Ollanius stood his ground and unloaded his [[Lasgun]] into Horus. Horus contemptuously swiped his talon, reducing Ollanius to red mist but giving the Emperor the time He needed.{{Fn|27g}}

With Horus briefly depowered and the Emperor greatly weakened, the ensuing contest became purely a physical one but the Warmaster was able to gouge out the Emperor's eye, mutilate his arm, crush his spine, and set his hair alight. The Emperor struck back, using the power of the reactivated [[Astronomican]] to shine its light directly into Horus' brain. The Warmaster fell into agony as he desperately tried to cloak himself in Warp power once more. However much to Horus' horror, he discovered that the Chaos Gods were now teaching him a lesson of sorts by deliberately denying him their power. Horus came to the realization that he had never been in control, and his Chaos masters were treating him as they would a disobedient slave. The realization combined with the brief absence of Warp corruption over his soul saw the old Horus the Emperor had once loved manifest once more.{{Fn|27i}}

===Aftermath===

===Timeline Summary===

*'''358014.[[M31]]''' - The Fall of [[Lion's Gate Spaceport]].{{Fn|30}}

*'''404014.[[M31]]''' - [[Perturabo]] abandons the siege.{{Fn|30}}

*'''560014.[[M31]]''' - [[Corswain]] and his [[Dark Angels]] land at the [[Astronomican]].{{Fn|30}}

*'''574014.[[M31]]''' - [[Jaghatai Khan]] recaptures the Lion's Gate Spaceport.{{Fn|30}}

*'''593014.[[M31]]''' - The Emperor faces Horus aboard the ''[[Vengeful Spirit]]''.{{Fn|30}} The flow of time on Terra essentially freezes by this point until Horus is killed.{{Fn|27i}}

**10,000 [[Dark Angels]] - Commanded by [[Paladin (Dark Angels)|Captain-Paladin]] [[Corswain]]{{Fn|13g}}

**Remnants of the [[Knights-Errant]], [[The Seventy]], [[Blackshields]], and [[Shattered Legions]]{{Fn|13b}}

**Small [[Space Wolves]] Force{{Fn|14}}

*[[Imperial Army]] - Billions of Troopers and Militia{{Fn|7a}}, ''de jure'' under [[Lord Commander Militant]] [[Adreen]]{{Fn|9l}}

***''[[Red Tear]]''{{Fn|15g}}

***''[[Monarch of Fire]]''{{Fn|15g}}

*[[Adeptus Mechanicus]] - Commanded ''de jure'' by [[Fabricator-General]] [[Zagreus Kane]]{{Fn|15d}}

**[[Skitarii]]{{Fn|15d}}

*[[Alpha Legion]] [[Operative]]s{{Fn|9a}}

*[[Dark Mechanicum]] - Commanded by [[Fabricator-General]] [[Kelbor-Hal]] and the [[Nine Disciples]]{{Fn|9d}}

**Dozens of [[Traitor Titan Legion]]s{{Fn|9a}}

***[[Legio Mortis]]{{Fn|9a}}

==Trivia==

{{Trivia}}

==={{Endn|Conflicting sources}}===

There are many differences with the narrative of the Siege of Terra as originally told in older sources with that of the [[Black Library (BL Publishing)|Black Library]] novel series. Most notably these include:

*In the original lore, [[Lorgar]] himself led the Word Bearers on Terra.{{Fn|1a}} However as of the events of the novel [[Slaves to Darkness (Novel)|Slaves to Darkness]], Lorgar is banished from Horus' sight for attempting to usurp him and instead the Word Bearers at Terra were led by [[Zardu Layak]].{{Fn|4}}

*The [[Sky Fortress]] was used for the defense of the Eternity Gate, not for the retaking of the Lion's Gate Spaceport by Jaghatai Khan.{{Fn|1d}}

==See also==

**{{Endn|10j}}: Dramatis Personae

*{{Endn|11}}: [[Morningstar (Audio Drama)]]

*{{Endn|13}}: [[Saturnine (Novel)]] Dramatis Personae

**{{Endn|13a}}: Part 1, Chapter 2-3

**{{Endn|20f}}: Aftermath

**{{Endn|20g}}: Cover

*{{Endn|22}}: [[Echoes of Eternity (Novel)]] - Dramatis Personae

**{{Endn|22a}}: Chapter 3

**{{Endn|24q}}: Dramatis Personae

**{{Endn|24r}}: 1:xvii

*26: [[The End and the Death: Volume II (Novel)]]:

**{{Endn|26a}}: 7:xxvi

**{{Endn|27l}}: 9:vi

**{{Endn|27m}}: Interludes: Distant Sons - i

*{{Endn|29}}: [[System Purge (Short Story)]] - [[Era of Ruin (Anthology)]]

{{HHBattles}}