What occurred in the smoking aftermath of the Horus Heresy? Delve into the Loyalist Payback known as The Great Scouring.
Horus‘s campaign to strike towards Terra to achieve a quick and decisive victory had ultimately been defeated. The rebels were broken and in retreat, and Imperial forces now had the job of reacquiring all the territory they had captured. The Great Scouring saw the first mass galaxy-wide purge carried out by the Imperium as it sought to erase the taint of Horus’ treachery from its realm.
The Emperor’s Final Words
Before actually being confined within the Golden Throne, the Emperor had pronounced judgment on the rebels: they were to be driven into the hellish region of the Eye of Terror, which would hold them for all eternity. All records and memory of the Traitor Legions were to be expunged from the Imperial archives. Worlds such as Isstvan V and Davin would be scoured and the Traitors’ associated troops were to be destroyed or driven into the Eye. It would be as if the Traitor Legions never existed. Meanwhile since the death of Horus, the Traitor Legions had become splintered and dispersed.
Fighting continued for another seven years before the rebels were wholly destroyed or exiled. The Imperium fought not only the traitors but also Xenos that had taken advantage of the turmoil caused by the Heresy to plunder human worlds. Systems once thought unassailable to the Xenos threat were put under siege. During the campaign, loyalist forces realized the sheer scale of Chaos influence in the Imperium as world after world was discovered to have traitor presence.
Chaos Weeded Out
Many corrupted systems were cleansed and placed under the watch of the Inquisition. Horus’s death had not ended the fighting, it had renewed the loyalists against the rebels. Many worlds during the Heresy had refused to commit their forces to either side, or seceded entirely. Such indecision was punished by loyalist and rebel alike. These forces were bled white attacking rebel strongholds. Meanwhile, the Legions destroyed at the Drop Site Massacre were slowly re-established using what little gene-seed the survivors had managed to escape with.
With the Emperor confined to the Golden Throne and the Imperium leaderless but loosely organized under Roboute Guilliman, the forces of Chaos and all of the enemies of the Imperium swept down on the defenseless worlds which had been ravaged by the fighting during the Heresy. The light of the Great Crusade was gone to be replaced by a dark time in which death was far more prevalent and hope seemed far away. The forces of the Imperium were reorganized and redeployed and gradually the followers of Chaos were forced to flee west to the Eye of Terror. Eventually, the Imperium succeeded in stabilizing itself, but not without heavy losses of men and machinery.
The Ultramarines were a major factor in the success of the Imperium owing to their not taking part in the Siege of Terra due to fighting in the galactic east. Roboute Guilliman was the greatest military strategist alive and rallied the other Space Marine Legions to act as a bulwark against all enemies of the Imperium. The days following the Heresy were to be some of the darkest seen since the Emperor rose to power. Guilliman was said to have been everywhere during this period, rallying forces and reinforcing them with his Ultramarines before moving on to the next battle zone. Never once did the Space Marines take a step back, so strong was their faith in the Imperium and Guilliman’s tactics.
During the Scouring, great political changes were introduced into the Imperium, primarily overseen by Guilliman. The most significant of these was breaking apart the Space Marine Legions into Chapters as well as dividing the Imperial Army into the Imperial Guard and Imperial Navy. Both of these measures were intended to curb the power that any single man could wield in the Imperium, limiting the damage if another rebellion broke out.
The Great Scouring was followed by the period known as the Age of Rebirth.
Notable Planets Purged
Worlds associated with the Traitor forces are subjected to Exterminatus. These include Colchis, Barbarus, Cthonia, and Chemos. Olympia, homeworld of the Iron Warriors, endures a two-year siege by the Ultramarines and Imperial Fists but ultimately falls. Rather than let the loyalists occupy their world, the Iron Warriors detonated their missile stockpiles and left Olympia a barren wasteland