Drop Site Massacre
The Drop Site Massacre is the most commonly used term for the Battle of Isstvan V, one of the first open military conflicts between the traitor forces of the Warmaster Horus and the loyalist forces of the Emperor. Occurring at the outset of the Horus Heresy it is considered a rubicon moment in Imperial history, as it marked the moment where the traitor legions were irrevocably committed to galactic civil war. The effects and aftermaths of the battle - particularly amongst the Legiones Astartes - would still be echoing ten thousand years later.
Up until shortly before the battle of Isstvan V, Horus' rebellion was largely going according to plan. The first significant check to his scheme was met when Ferrus Manus, Primarch of the Iron Hands refused to join the rebellion, despite the entreaties of his close brother, Fulgrim. Manus' refusal forced Fulgrim and his small contingent of Emperor's Children marines to violently escape the rendezvous, a surprise action that inflicted considerable damage upon the Iron Hands' space fleet. Horus, accepting that Fulgrim could sway Ferrus Manus, had factored in the Gorgon's appearance on his side as part of his plans. This news - late in arriving as Fulgrim suffered delays caused by the warp while traveling from the meeting place to the Istvaan system - irritated the Warmaster as it meant Horus' forces would suffer additional and unplanned-for casualties, as well as those inflicted by the then-ongoing and also unexpectedly protracted Battle of Isstvan III. Horus subsequently ordered Fulgrim and his portion of Emperor's Children not assigned to Isstvan III to proceed to Isstvan V and create a fortifed position there.[1a]
Fulgrim chose a ruined pre-Imperial fortress and defensive wall emplacement on the lip of the Urgall Plateau as the basis for his fortification. With the aid of Dark Mechanicum elements attached to Horus' forces he swiftly created a vast network of trenches, bulwarks and redoubts around this wall and fortress, emplacing anti-aircraft batteries and surface-to-orbit missile silos all along and behind the perimeter.[1b] The fortress itself he partially rebuilt, reinforcing it and even installing a protective void shield[2a] system. This would serve as Horus' command post in the battle to come.[1b]
Meanwhile, once news of the rebellion reached Terra, Rogal Dorn, the Primarch of the Imperial Fists, was placed in command of the Imperial military by Malcador the Sigillite. He transmitted the order for a strike force of no less than seven entire Legions - the Iron Hands, the Salamanders, the Raven Guard, the Word Bearers, the Night Lords, the Iron Warriors and the Alpha Legion - to travel to the Isstvan system and destroy the traitor forces. Unable to move his entire legion to Istvaan on time (due to the damage to his fleet inflicted by Fulgrim during his escape from their disastrous meeting), Ferrus Manus elected to travel in the largely undamaged vessel Ferrum, along with his entire Terminator elite, the Morlocks.[1c]
At the conclusion of events on Istvaan III, Horus moved his forces to Istvaan V, taking up position in Fulgrim's defensive work. Horus' forces at this time included the majority of his own Sons of Horus legion, as well as those of the Emperor's Children, Death Guard and World Eaters legions. Alongside these Astartes units he also commanded millions of traitor Imperial Army forces under Lord Commander Fayle and Titans of Legio Mortis. One account of Horus' order of battle at Istvaan V puts his Astartes troop strength at around 30,000[1b] (accounts on the numbers of combatants conflict; see notes at bottom of the page).
The fleets of the Salamanders and Raven Guard arrived at Isstvan V first, finding local space apparently deserted. Achieving orbital superiority uncontested, they undertook observation and reconnaissance missions, able to map out the traitor's position accurately and realising it required a full-scale ground assault to destroy it. The Iron Hands contingent arrived next and the three Primarchs hesitated, both as their orders apparently stipulated that the seven Legions should attack together and because they realised that they could not ensure victory without additional support. Upon learning that the four remaining Legions were mere hours away from translating in-system, Ferrus Manus convinced his brothers Corax and Vulkan to attack immediately, secure in the knowledge that they would receive reinforcements in the field from the inbound Legions. The plan was swiftly decided; Corax was to secure the right flank of the battlefield, Vulkan the left and Ferrus Manus would push through the centre of the enemy line.[1d]
Upon the surface, the traitor Astartes assembled in line formation in front of the defensive wall, with Army artillery and other long-ranged support units kept to the rear. A notable exception to this was the Imperator Titan of Legio Mortis, the Dies Irae, which took up position near to the Astartes, intent on performing a close-support role.[1d]
The First Wave
The loyalists commenced the attack by initiating a short orbital barrage all along the length of the traitor line. This proved almost totally ineffective due to the strength of the defensive system (as indeed the loyalists had earlier realised) but succeeded in throwing off the anti-air platforms long enough for an immediate massed drop pod assault to hit the Urgall Plateau directly in front of the traitor position. One account places the total amount of loyalist marines hitting the dirt in this assault as over 40,000 (See Notes). In one of the first pods to land, Ferrus Manus led his elite Iron Hands units directly into an incoming storm of gunfire. Dies Irae opened up, eliminating hundreds of loyalist marines in these first moments. Under cover of this mammoth weight of fire a unit of around a hundred traitor marines - made up of units from the Death Guard and Sons of Horus - sallied out to close and engage with Ferrus Manus' advance unit, but were quickly decimated and forced to retreat in the face of the primarch's rage. At roughly the same time the lead element of the Salamanders under Vulkan hit their portion of the enemy line. The traitors responded with a pinpoint artillery strike directly upon Vulkan's position... which barely fazed the Salamanders primarch, although it did slay several of his Firedrakes. With two primarchs penetrating the traitor defences and shrugging off everything thrown at them, the initial stage of the battle is considered to be tilted in the loyalists' favour.[1d]
Further improving the loyalist situation, the support elements of the loyalists' first wave chose this time to land on the planet. Touching down in a pre-arranged landing zone at the other side of the Urgall Plateau from the traitor position, further loyalist Astartes forces moved out from their Thunderhawk and Stormbird transporters, while heavy landers beachd Imperial armour units (including Super Heavy Tanks) and artillery. With casualties taken into account, it's now reckoned about 60,000 Astartes are engaged in the battle.[1d]
The traitor line bent like a bow under the weight of this attack, with Ferrus Manus' spearhead pushing in the furthest. At this point of wavering strength on the part of the defenders, Corax and the Raven Guard made their move, slicing into the traitor flank with a massed jump pack assault. However, this tactic was met with a riposte organised by Angron, primarch of the World Eaters, who had secreted many units of his legion in ambush positions, apparently for just this eventuality. His brutal warriors managed to slay many Raven Guard, halting the advance of the black-armoured Astartes. The loyalist push as a whole slowly ground to a halt at this point, as Mortarion stiffened the resolve of his Death Guard and Ezekyle Abaddon and Horus Aximand moved amongst the Sons of Horus, inspiring them by slaying any Imperial who got within their reach. Ferrus Manus' own constant forward movement finally ended when his Iron Hands ran directly into the waiting formations of Emperor's Children Noise Marines, who devastated the attacking Morlocks with their sonic weaponry.[1d]
This halt in forward movement for the Imperials did not last too long; heavy armour brigades fought their way across the plateau to arrive behind the Iron Hands, their heavy weaponry scattering the Noise Marines and freeing up the Terminators to continue their advance. Changing target, the massed Imperial armour units then concentrated their firepower on the ravening Dies Irae, stripping its voids and forcing it to cease firing upon infantry and switch to retaliatory tank-busting. Around this time of fragmentary combats, First Captain Julius Kaesoron of the Emperor's Children met First Captain Gabriel Santar of the Iron Hands in single combat, with Kaesoron emerging triumphant.[1d]
The Second Wave
With combat seeming about to enter a disorganised phase, the loyalists were once again bolstered with reinforcements. It was at this time, about three hours after the beginning of the battle[1e], that the second-wave Legions arrived. The Word Bearers, Iron Warriors, Night Lords and Alpha Legion executed successful combat landings into the already-established imperial drop zone, immediately fortifying it and securing the flanks of the plateau itself, with the Night Lords and Alpha Legion taking the flanks, the Iron Warriors the high ground behind the drop zone and the Word Bearers forming up on the newly erected defensive wall.[2b] The sight of this massive force - more than doubling the Imperial presence on Istvaan V in one stroke - appeared to force a general fighting retreat on the part of the traitorous forces, with even Angron, Mortarion and the Dies Irae seen pulling back from combat.[1e]
Just at this moment, Ferrus Manus located Fulgrim's command position in the centre of the traitor line and ordered his Morlocks to assault it, despite Corax's urgings to fall back. Corax believed that the battered first-wave Legions should take advantage of the lull in fighting to resupply in the drop zone encampment and return with the fresh second wave, and in fact both the Raven Guard and the Salamanders took this course of action. When Ferrus Manus refused to follow them, his two brothers apparently chose to leave him unsupported rather than reinforce his sudden forward push.[1e]
The heavy Terminator elite of the Iron Hands struck the Emperor's Children command redoubt hard, engaging in battle with the significantly outnumbered Phoenix Guard. In their stead, Ferrus Manus confronted Fulgrim, choosing to duel him with words rather than weapons. At the other side of the battlefield, the Salamanders and Raven Guard, low on ammunition and having suffered heavy casualties, got to within a hundred metres of the landing zone fortifications when vox-contact with the second wave abruptly went dead. A single flare was fired from Horus' command post: a signal to the second wave legions, now revealed as traitors, to open fire. This first salvo decimated the unsuspecting Raven Guard and Salamanders.[1e]
Holding an immediate conference, Corax and Vulkan found themselves disagreeing over what to do; Vulkan advocated making their way to their own dropships and digging in to resist an attack, while Corax insisted that they should take whatever means possible to immediately evacuate the area. Unable to agree a unified plan, Corax - realising the battle was lost - turned from his brother and ordered his legion to retreat by any means necessary.[3a]
On the other side of the battlefield, the supposedly retreating traitor legions about-faced and threw themselves at the Iron Hands, apparently slaughtering them to the last marine. In the midst of this carnage, Fulgrim and Ferrus Manus, once the closest of brothers, dueled to the death. After a titanic conflict Fulgrim emerged the victor, and beheaded Ferrus Manus. Immediately afterwards, the horrified Primarch of the Emperor's Children, seeking oblivion for his sin, gave in to daemonic possession, for a time effectively ceasing to exist as an independent entity.[1e]
The general advance of the traitors included the newly revealed second wave forces, with Lorgar, Kor Phaeron and Erebus of the Word Bearers in the vanguard. Due to the positioning of the legions, the Word Bearers primarily found themselves facing Raven Guard marines, and it was in the midst of this fighting that the hardest hitting units of both legions would meet in brutal combat. The Gal Vorbak - the Word Bearers' elite Possessed formation - leapt upon Corax, attempting to swarm him in close combat. The Primarch of the Raven Guard proved so formidable a warrior however, that even Astartes enhanced by daemonic possession were no match for him and he slew them freely. In an attempt to stop this slaughter of his favoured sons, Lorgar used his normally stunted and weak psychic powers to charge through the throng of warriors, arriving just in time to prevent the deaths of such Gal Vorbak as Argel Tal. Corax and Lorgar then dueled, with Corax swiftly gaining the upper hand over the less warlike Lorgar and preparing to execute him. Lorgar was only saved from death by the sudden intervention of Konrad Curze, the Night Haunter, who threw himself at his Raven Guard brother. Fresh to the battle and a lethal warrior, Curze proved superior to the tired and wounded Corax and drove him off.[2c]
It was at this point in the battle that the day could truly be called a massacre. Massively outnumbered, the Raven Guard and Salamanders were dying, but dying slowly. Until that is, the return to the field of Mortarion, Angron and the Dies Irae, who caused tens and tens of deaths. Fulgrim - now secretly possessed by a daemon - quit the field completely, leaving the Emperor's Children to be commanded by Eidolon and Lucius. Finally, Horus himself entered the slaughter, leading his own Terminator elite; the Justaerin of Captain Falkus Kibre.[1f] At the climax of the massacre the Iron Warriors launched a tactical nuclear missile at Vulkan's position, annihilating those Salamanders with him and ending Vulkan's participation in the battle.[1f]
The hopes of Imperial retreat were largely quashed when the Iron Warriors turned their guns on the first wave dropships, destroying them; in addition, the orbital battle between the fleets of the various Legions resulted in the almost total destruction of the surprised loyalist vessels.[2c] Despite this, small pockets of Raven Guard and Salamanders manged to break out of the massacre site, boarding whatever vessels they could find and taking off. More Raven Guard than Salamanders escaped, although the Salamanders did manage to take some surviving Iron Hands marines away with them. Corax managed to get aboard a Thunderhawk[1f], but it was shot down almost immediately, crashing outside the Urgall Plateau.[3a]. Meanwhile, regenerating from his wounds due to being a Perpetual (a fact unknown to the traitors), Vulkan ended up a prisoner to Konrad Curze aboard the Nightfall, Curze's flagship.
Among those small groups of loyalists who escaped the trap were Cadmus Tyro, commanding a mixed group of survivors on the ship Sisypheum, and Artellus Numeon, leading a force of Salamanders aboard the Fire Ark.
The Raven's Flight
Corax survived the crash and quickly managed to regroup his Raven Guard survivors, where much to his dismay he discovered that the casualty estimate for his entire legion was between 75 and 90 percent.[3a] He assembled these survivors (numbering four thousand; see Notes) atop a highlands hill, but a roving Iron Warriors armour column threatened to unmask his position. Electing to destroy them, he swiftly organized an ambush with his surviving tactical and assault units and wiped it out, before moving his hiding place.[3b]
Thirty days after the drop-assault, the hiding Raven Guard had heard no word from either the Salamanders or Iron Hands and felt that their future looked bleak. Corax ordered that his men should move to an area known as the Lurgan Ridge and dig in there, whilst he undertook a solo reconnaissance mission of the drop site. Even though it was still being used by traitor units, Corax was able to completely escape detection by using his 'invisibility' or psi-clouding power. While recon may have been his stated purpose for this dangerous mission, Corax spent most of his time on the Urgall searching for the corpses of his brothers. He did not find them.[3c]
Ninety-eight days after the massacre, the Raven Guard were pinned down by their hunters; Angron and his World Eaters. The World Eaters force (massively outnumbering the three thousand surviving Raven Guard) hit them with a Whirlwind artillery bombardment, but before they were able to follow this up and close in for the kill they came under concentrated orbital bombardment and air-to-surface missile strikes from suddenly appearing Raven Guard dropships. These dropships, under the command of Imperial Army Praefactor Valerious and part of a mission led by Raven Guard Commander Branne, quickly managed to evacuate the Raven Guard survivors in the brief window they fought for themselves, allowing Corax to finally leave Istvaan V...but with only three thousand of the eighty thousands marines he initially landed with. Unknown to either Horus or Corax, Alpharius had allowed the Raven Guard's escape as part of his own plans regarding the Legion.[3d]
The main sources for the Drop Site Massacre contradict the numbers of Astartes present at the battle. Fulgrim by Graham McNeill gives 30,000 marines for the traitor legions total and 40,000 marines for the first wave loyalist total, resulting in total involvement of 70,000 Astartes from 7 legions before the second wave drops.
On the other hand, Raven's Flight by Gav Thorpe states that the number of Raven Guard present was 80,000, meaning that in one source the number of marines in one legion alone is more than the total initial number of combatants in the other. In Deliverance Lost by Gav Thorpe, Corax states that he left Istvaan with 5,000 warriors and confirms that at least 75,00 Raven Guard died on Istvaan which proves Corax started with at least 80,000 warriors. This figure was indicative of Black Library's decision to retroactively (and drastically) increase the size of the Space Marine legions.
Given that both later books in the series and the new Forge World Horus Heresy rulebooks give larger legion numbers, the numbers presented in the earlier novel Fulgrim should no longer be considered canon.
- 1: Fulgrim (Novel) by Graham McNeill
- 2: The First Heretic (Novel) by Aaron Dembski-Bowden
- 3: Raven's Flight (Audio Book) by Gav Thorpe
- 4: Deliverance Lost (Novel) Chapter 2
- 5: Vulkan Lives (Novel)
- 6: Angel Exterminatus (Novel)