Drop Site Massacre - The Phoenician and The Gorgon: As Horus made the opening moves of his rebellion on Isstvan III, Ferrus Manus' oldest and dearest friend Fulgrim was ordered by the Warmaster to meet with the Iron Hands' primarch aboard his flagship Fist of Iron in the hope that he could be swayed to the side of the Traitor Legions who now served Chaos. Fulgrim had sent the bulk of his IIIrd Legion and the 28th Expeditionary Fleet on to meet Horus and the 63rd Expeditionary Fleet in the Isstvan System while he and a small force aided the Iron Hands' 52nd Expeditionary Fleet in retaking the world of Callinedes IV from Orks.Great bonds of friendship and brotherhood had long existed between the two Legions, and Fulgrim felt that he could convince Ferrus of the righteousness of Horus' cause. Fulgrim's hope proved disastrously wrong and the meeting of the two Primarchs in Ferrus' private inner sanctum in his flagship's Anvilarium did not go well, as Ferrus was utterly outraged that his brothers would turn against their father the Emperor. The meeting ended in violence as The Gorgon made his difference of opinion over continued loyalty to the Emperor known to the Phoenician with his weapons, determined to stop Fulgrim's betrayal of the Imperium before it could begin. Ferrus attempted to use his silvery necrodermis hands to destroy Fulgrim's golden sword Fireblade, but the resulting explosion when he failed to break the weapon knocked him unconscious.Fulgrim intended to kill his unconscious brother with the weapon he had forged for him, the warhammer Forgebreaker, but proved unable to kill his oldest friend despite the promptings of the Slaaneshi Daemon that now corrupted his soul. Instead he took the wonderous weapon that he had once crafted in brotherhood for Ferrus as a reminder of their former friendship, and left behind Fireblade, which Ferrus had forged for him. When Fulgrim emerged from Ferrus' inner sanctum, he gave a signal to his elite Phoenix Guard, who instantly beheaded all of the Iron Hands Morlocks Terminators who served as Ferrus' own elite bodyguard with their Power Halberds.The Emperor's Children also nearly slew the Iron Hands' First Captain Gabriel Santor. Fulgrim successfully fled the Iron Hands' expeditionary fleet in his personal assault craft, the Firebird, as he ordered his warships, the battle barge Pride of the Emperor and its escorts, to open fire upon the ships of the Iron Hands' 52nd Expeditionary Fleet. This surprise attack crippled the Iron Hands force and provided a distraction while Fulgrim and the Emperor's Children warships fled into the Warp to rendezvous with the rest of their 28th Expeditionary Fleet in the Isstvan System.The Warmaster was enraged at Fulgrim's failure to convert their brother Ferrus to their cause. Nevertheless, he still had to make preparations for the inevitable response of the Emperor, which was likely to arrive more quickly than anticipated and the Traitors needed to be prepared for it. Fulgrim was tasked to take a detail of the Emperor's Children to the ruins of the alien fortresses that existed on Isstvan V and prepare that world for the final phase of the Isstvan operation. Though the Phoenician recoiled at the horrifying prospect of the menial role placed upon him, Horus soothed his brother's monstrous pride when explained that the Isstvan V phase of his plan was the most critical, and he could entrust this vital task to no other.Fulgrim supervised the vast teams of Dark Mechanicum earthmovers as they shifted the black sand of Istvaan V and formed a vast network of earthworks, trenches, bunkers and redoubts that stretched along the ridge of the Urgall Plateau. Laagers of anti-aircraft batteries were set up in the shadow of the walls, and mighty orbital torpedoes on mobile launch vehicles hid in the warrens of an ancient alien fortress. Fulgrim had set up his command within the remains of the keep and begun the work of ensuring that it would be a bastion worthy of the Warmaster. If the Emperor’s Legions wanted to destroy the Traitors, they were going to have to come down to the surface of Istvaan V to do so, as no obital bombardment would be powerful enough to dislodge the defenders or crack their resolve.