Drop Site Massacre - The Harrowing: Lesser troops would have given up and accepted their fate in the face of such overwhelming opposition, but the warriors of the Salamanders and Raven Guard were Astartes. So they fought like never before, knowing their doom was at hand, and desiring to make the Traitors pay in blood for every one of their number that fell. Caught between two armies, the first wave of the Loyalist forces was systematically massacred. Unrelenting gunfire from the Iron Warriors at the drop site, and the resurgent forces along the Urgall Depression crushed the Salamanders and Raven Guard in a terrifying vice, and cut them to pieces in a murderous storm of fire and blood.Warriors of the Alpha Legion and Word Bearers followed their leaders onto the black plains of Istvaan V, their guns blazing and their Chainswords bright as they cast off the last remnants of their loyalty to the Emperor and turned their weapons on their brothers. The Dies Irae killed scores with every shot of its mighty weaponry, striding like a giant daemon of legend through the benighted slaughter. White-hot fire blossomed amongst the Loyalists and killing flames sawed across the black desert, vaporising men and turning sand to glass. Traitor tanks roared from the Urgall Hills, weapons blazing and crashing the wounded beneath their tracks.Refusing to surrender, the remaining Raven Guard and Salamanders Astartes stubbornly defended themselves, trying to hold off the inevitable slaughter for as long as possible. Though they suffered an atrocious number of casualties, the Loyalists managed to hold their own, until the Primarchs Mortarion of the Death Guard and Angron of the World Eaters joined the fray. Bolstered by the support of the infamous Imperator-class Titan Dies Irae, the Traitors killed tens of thousands of Loyalist Astartes.At the height of the massacre, with victory in his grasp, the Warmaster took to the field of battle, surrounded by Captain Falkus Kibre and his Justaerin Terminators. The remnants of Horus' Mournival fought alongside him, the Warmaster's magnificent black armour and amber chest adornment gleaming bloody in the firelight. The killing fields of Isstvan V ran red with the blood of the Loyalists, their brave attempt to halt the rebellion of Horus now rendered little more than ragged flesh and blood that fought for the last shreds of honour left to them.Any hope for escape for the Loyalists was quickly crushed when the traitorous Iron Warriors destroyed the first wave's drop ships. The Loyalist starships still orbiting the embattled planet were also largely annihilated by the vastly superior numbers of the Traitor fleet after the second wave's warships turned their guns upon the vessels of the true Loyalists. Despite the odds arrayed against them, some of the Loyalists on the ground managed to survive -- they miraculously escaped through the tightening cordon of Traitors that surrounded their position.The Raven Guard fared better than the Salamanders in escaping the brutal massacre. But the Salamanders managed to assist a few surviving Astartes from the decimated Iron Hands Legion to also escape the slaughter. As for Vulkan, he and his Salamanders had at last been driven together to fight a desperate, final stand and were perhaps the last to fall, encircled by a thousand foes and engulfed in a cataclysm of firepower. At the climax of the massacre the Iron Warriors launched a tactical nuclear missile strike at Vulkan's position, annihilating those Salamanders with him and ending Vulkan's participation in the battle. Imperial history did not record the ultimate fate of the surviving Salamanders, though an unconscious Vulkan survived the assault and the nuclear blast only to be taken prisoner and tortured for long solar months by his brother Konrad Curze.The Alpha Legion were the first to fall back from the slaughter, their deed done, their objectives claimed. After, it is said, the Sons of the Hydra withdrew in whispered order, and in perfect stillness watched the last act of murderous despoil unfold as the guns of the Iron Warriors at last fell silent and the rest took their fill of trophy taking, dark ritual and madness unfettered. The grievously wounded Raven Guard's Primarch just barely managed to board a fleeing Thunderhawk gunship to make good his escape, but was thwarted in the attempt when it was shot down almost immediately by the gunfire of the Traitors. The badly damaged ship crashed on the outskirts of the Urgall Plateau.On the black sands of Istvaan V more than 200,000 Space Marines lay dead, a Primarch had been slain and two others were missing, presumed dead, their Legions all but wiped out. With them died the Emperor's own dream of dominion of the stars.