Siege of Terra
|Siege of Terra|
|Status||Pyrrhic Loyalist Victory|
|Traitor Legions||Imperium of Man|
|Commanders and Leaders|
|Horus, Angron, Mortarion, Angron, Fulgrim, Perturabo, Magnus the Red, Zardu Layak, Kelbor Hal||The Emperor, Sanguinius, Rogal Dorn, Jaghatai Khan, Vulkan, Malcador the Sigillite, Constantine Valdor|
|Sons of Horus, Death Guard, World Eaters, Emperor's Children, Thousand Sons, Iron Warriors, 5000 Word Bearers, Night Lords, Traitor Army forces, Dark Mechanicum, Traitor Titan legions, daemons||Imperial Fists, Blood Angels, White Scars, Adeptus Custodes, Sisters of Silence, Knights-Errant, Imperial Army, three Titan Legions|
|Massive Heretic Astartes casualties, massive Traitor Army losses, massive Traitor Titan losses, massive Dark Mechanicum losses. Horus slain.||Massive military and civilian losses. Malcador the Sigillite slain. Sanguinius slain. Emperor mortally wounded and interred into Golden Throne.|
|Traitors driven from Terra and into the Eye of Terror. Death of Horus and crippling of the Emperor. Great Scouring Begins|
"He waits no longer. It begins now."
- – Sanguinius on the 13th of Secundus, 014.M31
The Siege of Terra was the end of the Horus Heresy in Warhammer 40,000. If the Horus Heresy can be considered the most important series of events in the 40k universe(*cough*War in Heaven), then the Siege of Terra itself could be considered the single most important event. It is also possibly the most fucking awesome event: brother fighting brother, the mighty guns of Titans blowing fortifications to shreds, Imperial Army soldiers leading charges against the traitorous forces even though they know it's suicide and Ollanius Pius
It was Horus's big attempt to off his daddy and so be the true Emperor of the galaxy (for Chaos of course!). He brought a load of his traitor legions, millions of corrupt Imperial army personnel and mutants, the part of the Mechanicus that had gone over to his side and a whole load of daemons to boot. On his side the Emperor had three legions, his custodians and the loyal imperial army regiments of Terra and you know what? The Emperor went and won anyway (granted it was because the Emperor offed Horus before his legions could crack the Imperial palace but still, victory for the home team!).
The Solar War
Dorn began fortifying Terra immediately after getting word of the Heresy, knowing that it would always be Horus's eventual goal. Despite being removed from the larger battles of the Heresy, the Solar System was touched by the conflict, with Mars rebelling and numerous sleeper agents and cults trying to destabilise the Throneworld. Despite this Dorn managed to do the best he could, turning Terra into the most heavily fortified system in the Imperium. He even managed to blunt part of the traitor advance at the Beta Garmon cluster before getting ready for the final rumble they had known was coming.
Terra was unique in that it had two artificial Mandeville points inside the the Solar system itself, created during the Dark Age of Technology. Dorn fortified the likely approaches from the outer edge of the system and built up huge defences around the two internal jump points. The traitors, however, were busy too: infiltrators and covert operatives sabotaged loyalist assets across the system. The Iron Warriors were the first Astartes into the breach, using huge up-armoured Space Hulks as fireships to wear down the defenses before sending their main fleet through to engage the combined Fists and Scars fleets. The inner system conflict went on for a bit, with the loyalists managing to hold out enough to slow down the advance at least for a little while.
However, under Magnus's direction, the traitors turned the Shrine of Unity comet into a vast warp gate that allowed Horus, Angron, and Fulgrim's fleets to jump right past most of the rings of defense Dorn had come up with. On the Phalanx, Dorn was preoccupied with a daemon incursion and could do little to stop the huge fleets that were now mobbing for Terra. The Martian traitors, free from the blockade that had hemmed them in for years, joined up with Horus. The Solar War had been lost barely after it had begun. The rest of the Loyalist fleets, knowing they could never hope to fight even a fraction of the vast traitor armada, regrouped on the edge of the system, along with the Phalanx, waiting for the moment they could make an effective strike against Horus. There were early plans for the Emperor to be evacuated to the Phalanx and escape Terra, but these were made by people unaware of what Big E was doing in the basement of the palace.
The Siege Begins
"Father! I have come for you!"
- – Angron upon making planetfall, 15 of Quartus, 014.M31
Uncontested, most of the traitor armada held in orbit above the Palace and began bombarding the Aegis, the vast shield network protecting the entire palace complex. Unlike regular void shields, the Aegis consisted of multiple overlapping layers of shields that individually regenerated as fast as they could be depleted by bombardment. On the ground, the Palace was protected by colossal networks of walls and bastions, static defences, and vast numbers of Imperial Army units bolstered by hordes of press-ganged conscripts. Unknown to almost everyone, the Inner Palace was also protected by a psychic ward generated by the Emperor that would royally fuck up any daemon that set foot near it, daemon primarchs included.
The rest of Terra wasn't so lucky. Barring a few isolated holdouts, the rest of the planet was virtually defenceless. It should be noted that if the goal was to destroy Terra wholesale, it could have been easily accomplished by Exterminatus level weaponry. Perturabo, as the only non Chaos-ifed primarch, insisted on doing exactly that and grew increasingly angry at what he saw as an irrational and wasteful goal. But Horus was insistent that the Emperor had to be slain in person and so the Palace had to be reduced the old fashioned way. In all fairness, one must also ask if Exterminatus was even possible when a being like the Emperor was on Terra, to say nothing of the void shields and defenses on Terra itself. The daemon primarchs were kept in orbit, safe from the Emperor's wards, although this meant that Angron had to be imprisoned in the maze Perturabo had built to contain Vulkan to stop him from Leeroy Jenkinsing the whole thing as he had done at Istvaan III.
Hordes of mutants, beastmen, cultists, and traitor Army units were thrown at the conventional defenses. Entire wings of aircraft dueled above the Palace. Precision bombardments gradually weakened minute sections of the Aegis long enough for bombers to get through and destroy the projectors. The Dark Mechanicum landed siege camps at 8 points around the Palace, partly to surround it but also to act as the focus for a ritual that would enable the warp to take a foothold on the surface of the Throneworld. The Astartes were held in reserve on both sides whilst their more conventional forces softened each other up. The Death Guard were the first traitor Astartes to land on Terra, with the Khan and the White Scars riding forth on jetbikes and aircraft to meet them and wreck the Dark Mechanicum's siege camps. The Night Lords were the first Astartes to breach the walls of the Palace, albeit in small numbers; this attack also cost them their de facto commander, Gendor Skraivok. Sanguinius himself descended to help the mortal forces, acting as both force multiplier, decoy, and morale booster.
Battle for the Lion's Gate
While the Death Guard, Emperor's Children, and World Eaters each hammered away at a different section of the Palace walls, the traitors' first major effort at cracking the Palace itself was aimed at the Lion's Gate spaceport, the largest and tallest spaceport on Terra. It reached so high into the atmosphere that voidcraft could dock at its upper levels, meaning that the Traitor forces could more easily shuttle in reinforcements and materiel if they captured it. Horus tasked the Iron Warriors with taking the Gate, and in turn Perturabo assigned Warsmith Kroeger to lead the assault under the logic that Dorn would be expecting Pert to command such an important offensive personally and wouldn't be expecting whatever plans Kroeger came up with. Dorn, meanwhile, assigned Seneschal Fafnir Rann to lead the defense of the spaceport rather than First Captain Sigismund, since he was still angry with Sigismund for listening to Euphrati Keeler instead of obeying his orders. Kroeger went straight for the throat as it were, launching a massive combined-arms assault directly on the port with backup from the World Eaters and Emperor's Children, though the latter quickly got bored and left after taking a bunch of prisoners for unspecified purposes. Though the Imperial Fists held off the initial attack, Warsmith Forrix and a thousand Iron Warriors managed to infiltrate the Gate by using renegade Imperial Army units as literal meatshields. To aid the attack, the Dark Mechanicum inserted a technophagic virus into the spaceport's systems, and Zardu Layak, Abaddon, and Typhus performed a Nurglite ritual to infiltrate the Great Unclean One Cor'bax Utterblight behind the Emperor's psychic wards.
The Fists drove back several consecutive assaults from the Iron Warriors and World Eaters, but the technophage was screwing their sensors and comms all to hell and gone, seriously complicating efforts to coordinate the defense, and Forrix and his infiltrators were tying up troops that were desperately needed elsewhere. Rann finally called Dorn for backup and Dorn scraped up an additional three thousand Fists, which were literally all the troops he could spare at that point. Eventually, despite Rann's best efforts, the balance inevitably tipped in the traitors' favor, and Dorn arrived on scene just in time to order a general withdrawal from the spaceport to the inner defenses, though not before he killed Zardu Layak after a brief duel. With the Gate firmly in traitor hands, Perturabo started unloading Titans and consolidating his position.
Meanwhile, Euphrati Keeler and the Custodian Amon Tauromachian had been tapped by Malcador to investigate strange apparitions occurring behind the Palace walls. They eventually deduced that this was a daemon exploiting the faith of Imperial cultists to manifest itself inside the Emperor's psychic defenses, and focused on a cult called the Lightbearers which turned out to have been deceived into worshipping Nurgle instead of the Emperor. After Cor'bax had used the Lightbearers to physically manifest himself, Amon, Euphrati, and Malcador teamed up to slay the daemon. When Amon suggested that they should purge the rest of the Emperor's worshippers to prevent another such incident, Malcador answered that he would continue to let them exist until the Emperor himself said otherwise, in the hopes that he could weaponize their faith against the Chaos gods.
Battle for the Saturnine Wall
With the Lion's Gate lost, Dorn was now under a tremendous deal of pressure as he continued to coordinate the defense in the face of the unrelenting traitor assaults. Nearly all the Traitor Legions were committed to the battle, with the Death Guard, Iron Warriors, World Eaters, Thousand Sons, Emperor's Children, and Sons of Horus engaged in heavy fighting throughout the Palace, against which Dorn could only muster his own legion plus the Blood Angels and White Scars and their primarchs.
While taking a brief break in an abandoned garden, Dorn encountered Kyril Sindermann, who made an offhand comment about the Saturnine Wall trembling under the weight of the bombardment. From this, Dorn instantly realized that something was wrong with the defenses in that section and investigated. What he found was a potential catastrophe. The ceaseless bombardments from the traitor forces had caused the entire Imperial Palace and the tectonic plates on which it rested to shift by eight centimeters, opening a small but detectable fault line beneath the Saturnine Wall.
Certain that Perturabo would notice this fault and attempt to exploit it, Dorn began concocting a counterattack. Before laying out his plans, however, he called a council of war with Constantin Valdor and Malcador to explain to them his next move: he would have to start allowing parts of the Palace defenses to fall, as he simply no longer had the numbers or the materiel to hold everything. He identified four key parts of the defense that could not be allowed to fall to the enemy - the Colossi Gate, the Gorgon Bar, the Saturnine Wall, and the Eternity Wall spaceport - then chose the one he could most afford to lose based on his calculations, which was the spaceport. Though he would put on a show of defending it, Dorn knew that the port ultimately had to be sacrificed even though it meant letting the traitor forces control both of the Palace's main spaceports. He then assigned Sanguinius to hold the Gorgon Bar and Jaghatai Khan to hold the Colossi; he would personally oversee the defense of the Saturnine Wall and lay a trap in the hopes of bagging a significant enemy target, perhaps even Horus himself.
Perturabo had indeed spotted the weakness at the Saturnine Wall, though he had initially planned to use it only as a last-ditch ace in the hole. Abaddon convinced him to instead make it a focal point of the attack through a combination of flattery and unsubtle goading, suggesting that Perturabo's victory over Dorn would be tainted if it was won with the help of the Neverborn. Though the Lord of Iron nearly caved his face in for it, Abaddon won the argument, and immediately set out to assemble a spear-tip strike. Secretly, he was himself hoping to win a "clean" victory, without resorting to the use of daemons and sorcery, as he believed that using the Warp to win a war was beneath his dignity as an Astartes.
In the meantime, the battles for the Colossi and the Gorgon Bar escalated in scale and intensity. The defenders at the Colossi Gate were plagued by legions of flies which seemed to manifest from nowhere, forcing them to wear bulky protective equipment that lessened their effectiveness. Sanguinius was suffering under the weight of his psychic visions, which were coming with increasing frequency and intensity; nevertheless, he continued to fight on the front lines knowing that his mere appearance was heartening the defenders and raising their morale. At one point he singlehandedly killed a Warlord Titan then stared down its three accompanying Warhounds until they turned tail and fled. At the Colossi, Jaghatai and the White Scars led a few massed jetbike charges into the ranks of the Death Guard, destroying their siege engines, killing their Neverborn reinforcements, inflicting casualties, and generally delaying the XIV Legion's inexorable advance. The Adeptus Custodes were engaged at this point, with Constantin Valdor himself taking the field. At one point, Ahriman attempted to literally melt the Colossi bastion with sorcery only to be driven back by three White Scars Stormseers, who channeled the captured weather underneath the Palace's void shielding into an immense lightning storm.
Meanwhile, at the Saturnine Wall, Dorn had devised a simple but cunning trap. Its cellars and tunnels had been fortified and transformed into a series of Zones Mortalis, and he had assembled a five-hundred-man strong force of veteran Astartes, broken into seven kill teams led by Sigismund, Nathaniel Garro, Endryd Haar, Garviel Loken, Bel Sepatus of the Blood Angels, Helig Gallor of the Death Guard, and Maximus Thane. He had also enlisted the technoarchaeologist Arkhan Land to help him mend the fault line. Land swiftly devised a quick-setting form of rockcrete which could be pumped into the fault, sealing it permanently. Dorn didn't know who would be leading the assault, but he was hoping for Horus himself; once cut off and isolated inside the Palace walls, even the Warmaster would be relatively easy prey. On the other side, Abaddon was able to convince Fulgrim to lend him the entire Emperor's Children Legion for the assault on the Saturnine, and wrangled three companies of the Sons of Horus to form the spear-tip. The III Legion would attack from the front as a diversion, using three ancient siege engines borrowed from the Dark Mechanicum, while Abaddon and his Astartes burrowed up from beneath with Termite assault drills.
Unfortunately for all of them, they'd walked straight into Dorn's trap. When the Sons of Horus emerged from their assault drills, they were ambushed by Dorn's kill teams, who achieved total surprise. Nearly the entire assault force was wiped out, including the famed Justaerin Terminators and Catulan Reavers of the 1st Company and three of the four members of the Mournival. Garro decapitated Falkus Kibre of the Justaerin, while Loken killed Tybalt Marr, Horus Aximand, and Tormageddon. Just as the loyalists were starting to relax, however, Abaddon and a hundred Justaerin Terminators teleported right into their midst, triggering a giant brawl. Abaddon went on a killing spree but eventually absorbed a series of crippling blows from Bel Sepatus and Endryd Haar. Though he managed to kill them both, he sustained massive injuries and wound up pinned under Haar's corpse, with Garro poised to deliver the killing stroke. Luckily for Abaddon, he was teleported to safety at the last moment. Meanwhile, Arkhan Land began pumping hundreds of thousands of liters of his rockcrete formula into the fault. Though he was briefly interrupted by Horus Aximand, the plan otherwise went off without a hitch, and the fault line was permanently sealed. Some of the remaining Sons of Horus had yet to emerge from their assault drills and became trapped in the rockcrete as it set, ensuring that they would be entombed beneath the Palace forever.
While all this was going on, Fulgrim had unleashed a full-scale assault against the Saturnine Wall, leading off with three Donjon-class siege engines that had been modified with immense sonic weapons similar to those of the Kakophoni. The siege engines seriously disrupted the defense, at least initially, but the Imperial Fists and Army garrison were able to rally and funnel the III Legion into a chokepoint. Fulgrim, meanwhile, got into a duel with Sigismund atop the Wall. Though the Templar was able to land a few hits, Fulgrim's daemonically enhanced strength and speed gave him the upper hand. Before he could kill Sigismund, however, Dorn intervened and proceeded to pummel Fulgrim badly enough that the Phoenician threw a tantrum then took his legion and went home, abandoning the Siege entirely and costing Team Horus one of its most significant force multipliers. Fulgrim left fifty-six of his best warriors behind in an attempt to kill Dorn, but he and Sigismund were able to defeat them all, including Eidolon and Von Kalda. The entire assault wound up costing the Emperor's Children no less than eighteen thousand Astartes, along with all three of the irreplaceable siege engines.
This great victory had been purchased with an equally great loss: the fall of the Eternity Wall spaceport. Despite the defenders' best efforts to hold the port, they were faced with Angron and the main strength of the World Eaters. Angron issued a demand for the port's defenders to surrender and was met with a concentrated artillery barrage that literally atomized him, though being a daemon prince he didn't stay down for long. He and his legion immediately assaulted and seized the spaceport, killing everyone present. Many heroes of the Imperium died unheralded deaths at the Eternity Wall, including Knight-Commander Jenetia Krole of the Silent Sisterhood, Prefect Warden Tsutomu of the Adeptus Custodes, High Primary Solar General Saul Niborran, Captain Camba Diaz of the Imperial Fists, and Shiban Khan of the V Legion (no he didn't as per the next book). A lone Guardsman named Olly Piers died there also, defending a banner of the Emperor Ascendant against Angron's relentless charge, thus establishing the foundation for one of the Imperium's most enduring myths.
In the aftermath of these battles, Dorn and Sanguinius took stock of where they stood. The Gorgon Bar had held, and would continue to hold for two precious weeks more by Sanguinius' estimate. The repulse at the Saturnine Wall had cost the Traitor Legions dearly: three hundred of the XVI Legion's elite troops and eighteen thousand Emperor's Children dead, with Fulgrim and the rest of the III Legion having quit the field. Jaghatai Khan, having held the Colossi, was now preparing to retake the Lion's Gate. Better yet, Sanguinius' prescience had granted him a vision from within the depths of Angron's tortured mind: Nuceria had been destroyed - not merely razed as Angron and Lorgar had done during the Shadow Crusade, but obliterated by orbital bombardment. Dorn and Sanguinius both knew this could mean only one thing: Roboute Guilliman and Lion el'Jonson were on the way along with their legions.
Admiral Niora Su-Kassen, now in command of what remained of the loyalist naval assets in the Solar system, received indications of another fleet approaching from the outer edges of the system. She ordered the new arrivals to announce themselves, and was answered with a hail from Corswain of the Dark Angels: "We come to stand with Terra."
Duel of the Emperor and Horus
Like with any truly epic event, the siege only ended with the most motherfuckingest duel in the entire 40k fluff: the Emperor of Mankind against Horus, most favoured of the Primarchs and the living avatar of the Chaos Gods. If the Horus Heresy was the most important of a series of events, if the siege was the single most epic of those events, then the duel is the defining moment of the fluff and affected everything else that came after it.
During the duel, Horus had managed to mortally wound the Emperor (despite the Big E being a nigh-unkillable Perpetual), and would have finished him off, if not for the intervention of one Perpetual Guardsman (Oll Perrson/Ollanius Pius)/Imperial Fist/Custodian. He jumped in front of Horus as he was about to strike the final blow, and was killed. The Emperor, seeing how far his most favored son had fallen, decided "Fuck this" and OBLITERATED HORUS'S SOUL!
Although the Emperor managed to win and kill Horus, he was so badly wounded in the end he needed to be on 24/7 life support just to survive. So really when you come down to it,it was a draw; Chaos had been stopped then but only at an unthinkable cost to the Imperium.
What, besides the fact that it's the most important event in the 40k universe? Fine.
The Siege of Terra is also the theme for the Horus Heresy board game, in which you reenact the Siege itself. There. Happy? (Not really.)
The fa/tg/uy's explanation of the Siege Of Terra (for Dummies and BL Editors)
The main rule of warfare: As the number of combatants increases, the resemblance to complete uncontrolled insanity approaches infinity. And then you have to take into account the terrain...
Basically you start with a planet that's been nuked, polluted, and generally lived in for a few hundred thousand years too long. Everyone on it is fighting everyone else, constantly. Your basic unit of land is the Bunker, Vault 101 style. There isn't any natural plant life left so all the oxygen is made in vats with the food. Luckily this means you can build anywhere that isn't intensely radioactive and hence fight over those areas. Get Mega-City-One, nuke it and rebuild it a few times, and then you start to understand.
Then the Emperor comes along, and manages against all odds to conquer the place. Suddenly everyone isn't killing and dying all the time, and a population boom happens. So Emps organised the largest set of public works since the first colony ships. He rebuilds huge areas of the planet, and creates the Imperial Palace, the Astronomican, and a buttload more of cool shit besides. And what he gets is effectively one giant city, the second largest (after Commorragh) in the universe. "Huge" just doesn't do it justice as a description. Neither does "labyrinthine", "overpopulated", or "hothic nightmare". And this New Terra was mostly just thrown over the original foundations of whatever was there like a pile of gold bricks onto a rat maze. There are bunkers and emplacements still around that date back to the War Against The Men of Iron and even before.
Then the Heresy came, and the Emperor says to Dorn "Fortify this fucking madhouse". So now everything that didn't have a gun emplacement before does now, everywhere. Dorn walled in half the doors and windows, put hundreds of AA batteries on every roof, filled entire rooms with concrete just for a bit of reinforcement, built hundreds of miles of trenches, redoubts, bastions, emplacements, and backup walls, conscripted half the population into the army, and generally panicked because all of this would only ever be necessary if the solar system's defenses (the best in the galaxy bar none) have failed.
Then Horus arrives in orbit. He's punched through the space defenses at massive cost, but the war in space is far from won, and the Palace is just a flat no-fly zone, so he can't just pick and choose landing areas. So he bombards everything his ships can reach, fills the sky with Drop Pods, and tries to march on it.
Which is when Rule #1 kicks in and everything immediately gets megafucked for both sides. Ruined streets and bunkers make navigating a nightmare, communications are somewhere between impossible and actively detrimental, Drop Pods land off target, plans and back-up plans fall apart in seconds, daemons run amok, and the Primarchs are either constantly trying to out-Tactical-Genius each other or are too in the thick of it to relay any commands, so no one has a fucking clue what's actually going on in the big picture. It's Stalingrad writ large, but without even the merest hint of sanity and a thousand Space Marines charging into every breach. The inclusion of cackling daemons, rampaging renegade Guardsmen and abhumans, and bellowing daemon engines doesn't help the situation.
So it takes roughly 10 minutes of this menial bullshit for a load of the Chaos forces to get bored and just decide "Fuck It, Let's Just Wreck The Place". So now everything makes even less sense: entire companies are ignoring sensible objectives to go on the Chaos Marine equivalent of a bender. The Emperor's Children and the Night Lords rape, murder, and pillage the civilians of Terra so hard that even 10,000 years later they still live in fear at the memory, while the World Eaters are tearing around and hacking and slashing at anything they think might bleed. Only the Iron Warriors, the Death Guard, and the Sons of Horus are wholeheartedly tearing at the Palace, dedicated to rubbing it in Dorn's face like a bitch no matter what. And to the horror of the loyalists, they're succeeding. Brick by brick, the greatest military stronghold in the galaxy is falling.
Which sounds great for Chaos were it not for the simple fact it wasn't falling quickly enough. It was taking days to advance inches at massive cost, and Guilliman was en route with reinforcements, with Russ and the Lion and the remains of their Legions right behind him. If the siege wasn't ended before they got there, the traitors would likely lose. So Horus put all his cards on the table and lowered his battle barge's shields, goading the Emperor (who didn't know about the reinforcements - or maybe he did and was enacting a much greater scheme, see below) on board to hopefully kill him and force the defenders into a rout. Everything else is history.
The short story "The Board is Set" seemed to indicate that the Emperor and Malcador knew about the reinforcing loyalists from at least the beginning of the siege and were fully aware of the siege's outcome up to and including the Emperor's ascension to the Golden Throne. It also seemed to imply that Horus lowering his shield may have been so he could teleport down and attack the Emperor, not realising it was Malcador on the throne. Possibly the most epic level of Just As Planned.