Event · M31
Isstvan V Aftermath
Isstvan V Aftermath denotes the escape of surviving Loyalist Space Marines from Isstvan V after the Dropsite Massacre in the Horus Heresy. The event follows the landing of the Iron Hands, Raven Guard and Salamanders on the Isstvan system in the wake of the Isstvan III atrocity, when Warmaster Horus revealed his rebellion and the Legions that had joined him turned on their former allies on the surface of the planet. The engagement is recorded as the first large-scale battle of the Heresy, and the loyal contingents were largely destroyed in the open, with only a small proportion of the original force surviving the initial betrayal. The course of the escape is preserved in fragmentary and sometimes divergent accounts. Corax of the Raven Guard is recorded as withdrawing from the surface with a remnant of his Legion, while a scattering of Iron Hands and Salamanders, including elements loyal to the memory of the fallen Ferrus Manus, are said to have broken away by separate routes. The traitor Legions that pressed the attack, among them the Death Guard, Emperor’s Children, World Eaters and Sons of Horus, could not fully prevent these departures, and accounts differ on the precise numbers who escaped and on the fate of individual commanders such as Vulkan. The survivors were not a single coordinated force; several groups made their way out of the system independently, and some were later reunited only after long periods in hiding. In the graph of the Heresy, the aftermath binds the Isstvan system to the earliest phase of the war, in the opening period of the thirty-first millennium, and it marks the point at which the loyalist cause lost much of the strength of three Legions. The escapees are the origin of what later tradition calls the Shattered Legions, whose dispersed remnants conducted a war of attrition against the Warmaster’s forces while the main confrontation drew towards Terra. Contemporary events include the Battle of Calth and the later mustering of loyalist forces for the Siege of Terra, and the Iron Hands, Raven Guard and Salamanders are each described as having been reshaped in doctrine and leadership by what they endured on Isstvan V. Consult the Isstvan V location and the Dropsite Massacre entry for the surface battle itself; this entry concerns what followed.
See where Isstvan V Aftermath occurred on the galactic map during the Horus Heresy.