Isstvan III
"Order the guns to fire! Let the galaxy burn!"
- – Warmaster Horus Lupercal giving the order that got the whole ball rolling
Isstvan III (also spelled Istvaan because nobody at Black Library, Forge World, or anywhere else can agree on the correct spelling), was a Civilized World of the Imperium in the Segmentum Obscurus. It is infamous as the planet where the Horus Heresy truly began, as it was on Isstvan III that the loyalist elements of the Sons of Horus, Emperor's Children, World Eaters, and Death Guard were purged and Horus openly declared his intention to topple the Emperor from his throne and take his place as the Master of Mankind.
Overview[edit]
Isstvan and its system were originally brought into compliance by Corvus Corax and the Raven Guard during the later stages of the Great Crusade, around 994.M30. The Isstvanian military, supplemented by trained psykers known as Warsingers, had stoutly resisted the XIX Legion until being crushed at the Redarth Valley, but instead of a campaign of annihilation, Corax opted to offer the Isstvanians terms of surrender. The planet and its people were placed under the rule of Major Vardus Praal, a reliable and solid veteran who could be trusted to finish the process of compliance. Praal established his seat in the Choral City, Isstvan's capital, and the planet was swiftly integrated into the Imperium, becoming a model of compliance and cooperation. At first, anyway. Isstvan's location on the fringes of Imperial space meant that it was isolated from the rest of the Imperium from the start, a condition exacerbated by a local warp storm that made astropathic communications increasingly unreliable. Praal's efforts to subdue the remaining Warsingers and erase the planet's native religion were complicated by savage resistance from the native populace, and the last transmissions received indicated that riots and outbreaks of mass hysteria were on the rise, along with the murders of Imperial officials. Six years after the last official communique from the planet, the Death Guard picked up an astropathic distress signal with dire news: Governor Praal had turned his coat, resurrected the indigenous religion and its Warsingers, and his forces were now butchering any Imperial loyalists left on the planet. Upon learning of this, Horus Lupercal decided that Isstvan III would be the perfect place to begin his revolt against the Imperium. He ordered his fleet, along with those of the Emperor's Children, Death Guard, and World Eaters, to muster in the Isstvan system, ostensibly to return the planet to the Imperial fold.
The Battle of Isstvan III[edit]
After securing the outer reaches of the system, the combined Legion fleets assembled in orbit of Isstvan III. Horus laid out his plan of attack. The Death Guard would break through the Choral City's outer fortifications and eradicate or contain the garrison there. The World Eaters would storm the city itself, aiming to sever the transport arteries that the rebel troops would use to move reinforcements. The Emperor's Children would execute a surgical strike against the Precentor's Palace, Praal's residence and seat of power. Finally, his own Legion would attack the Sirenhold, a huge temple/shrine/tomb complex carved into the mountains to the east of the city. This complex had been abandoned after the Imperial takeover, but it had apparently been rebuilt and reinforced; Horus told the assembled commanders that he sought to tear the heart out of the rebellion by destroying its most sacred fane.
Secretly, however, Horus and his brother primarchs were planning to use the campaign to purge their legions of those Astartes who would never turn on the Emperor. This was reflected in the order of battle for the planetary assault. The assault forces from each legion were chosen apparently at random, with squads and companies being arbitrarily plucked out of their regular assignments and mashed together into new units. For the more perceptive men among the loyalists, this was their first hint that something was off about the whole thing. After a preliminary bombardment, the assault force was sent in. Despite some initial disorganization, the World Eaters and Death Guard ground steadily through the Choral City's defenses. Captain Lucius of the Emperor's Children slew Governor Praal in single combat, and the Sons of Horus seized and held the Sirenhold. At this moment of apparent triumph, however, Horus showed his hand. Virus bombs rained from the orbiting fleet onto the surface of Isstvan, unleashing the dreaded Life Eater virus into the atmosphere. The people of Isstvan III died in terror and agony as the Life Eater disintegrated people, animals, plants, and even bacteria at the cellular level, reducing them all to volatile sludge. Forewarned by Saul Tarvitz, many of the loyalist Astartes managed to take shelter, though hundreds were caught in the open and died with the rest of the planet. Horus then ordered the Vengeful Spirit to turn its guns upon Isstvan, igniting the volatile gases produced by the virus bombs and triggering a planet-wide firestorm that scoured Isstvan III to bare rock.
Despite this overkill, the loyalist Astartes managed to survive the bombardment and immediately hit their voxes to scream insults and questions such as "what the actual fuck bro?" at the orbiting fleet. Horus was prepared to order another bombardment until Angron took his legion down to get things done his way, forcing the Warmaster to commit to a ground campaign to finish the job. Despite being outnumbered and outgunned, the loyalist Astartes tied their traitorous brethren down for months, inflicting heavy casualties and delaying the start of Horus' offensive into Imperial space. Finally, the Warmaster realized that he needed to stop dicking around and ordered his troops withdrawn before dropping another bombardment on the planet, and so Isstvan III was left as a dead, lifeless rock.
Later Heresy[edit]
Nathaniel Garro returned to Isstvan later in the Heresy and found a traumatized and mentally broken Garviel Loken roaming the devastated world, slaughtering Isstvanians who had been resurrected as plague zombies while calling himself Cerberus and assuming that he was the last loyal Space Marine in the galaxy. He managed to snap Loken back to reality and took him off Isstvan to become one of Malcador's Knights-Errant. After this, Isstvan was once again forgotten, and faded into the mists of history...
The Ancient's Last Victory[edit]
"I am Rylanor of the Emperor's Children, Ancient of Rites, Venerable of the Palatine Host, and proud servant of the Emperor of Mankind, beloved by all! I reject you now and always!"
- – Rylanor, telling Fulgrim to take his Chaos bullshit and shove it up his cloaca like the badass he was.
Several millennia later, a group of sorcerers from the Thousand Sons detected a mysterious transmission emanating from a remote region of the galaxy. The broadcast consisted of only three words: "The Ancient awaits." Curious, they traced the signal to its source and found that it was emanating from a dead ball of rock in orbit of a forgotten star. Upon landing on the planet's sere, scorched surface, they realized that they had in fact made landfall upon Isstvan III itself. They followed the broadcast into a half-collapsed hangar deep beneath what had once been the Precentor's Palace. There, they found a battered, broken Dreadnought lying next to an unexploded virus bomb. This Dreadnought was revealed to be none other than Ancient Rylanor of the Emperor's Children, who had been trapped on the planet since its destruction thousands of years prior. Despite having been driven to near-insanity by his long isolation, Rylanor had remained loyal to the Emperor. The purpose of his broadcast was revealed when Fulgrim arrived in all his daemonic splendor. Fulgrim attempted to convince Rylanor to hop on the party bus with the rest of the III Legion, but the Ancient told him to get fucked in glorious fashion and set off the virus bomb. One of the Thousand Sons attempted to contain the blast, but one of the other sorcerers, inspired by Rylanor's unshakable loyalty and disgusted by Fulgrim's corruption, killed him and let the bomb go off (the three sorcerers psychically agreed to let it detonate, but the guy holding up the bomb couldn't drop the shield so he allowed his brother kill him). The detonation killed Rylanor and the Thousand Sons and temporarily unmade Fulgrim, though as a daemon prince it couldn't permakill him. That said, it had one lasting effect: Fulgrim's pride was permanently wounded by Rylanor's rejection, a wound from which he could never recover.