Orphean War - The Orphean Decree and the Orphean Salvation Campaign: Regrouping and reinforced by fresh contigents of troops, warships and Astartes, the Imperium has been struggling to hold the Necron advance back. Cut off, the forces of Amarah Prime and Hydroghast were the next to fall, although scattered pockets of resistance boldly hold on. Having been stripped of most of its defences by Sector Governor Calibron Laan, the Arcantis Cluster became a prime target for the next Necron assault.Although the phalanxes deployed in these first attacks were considerably smaller than those encountered on Amarah, they still caused considerable havoc. On the Mining World of Kaelogeddon, the entire 47th Armoured Regiment of the Death Korps of Krieg was lost in the Battle of the Outhal Depression, but their sacrifice enabled the Imperial forces to encircle the Necron spearhead and ultimately destroy it. Many of these bloody victories went unrecorded, for the Imperium had more pressing matters to address.By 995.M41, it seemed obvious that the Orphean War was nearing its bitter conclusion, the millions of men and women thrown at the enemy only reaching a bloody and ultimately untenable stalemate. Left unchecked by the massive redeployment necessary to slow down the Maynarkh Dynasty, the Chaos element in the Chemarium System was left to fester, until the servants of the Ruinous Powers invaded outlying worlds. They too would soon be fighting desperately to repel the Necron invasion forces.At the forefront of the Necron advance in the Arcantis Cluster, Imperial attrition rates soon reached 60% with no improvement or gain to claim. Fresh probing attacks were directed towards Amraphel and the Forge World of Myre, and Imperial tacticians are certain that the next big Necron push will target those worlds. The remainders of Battlefleet Orpheus and Battle Group Salvation desperately try to hold the line, but following the severe losses of the Battle of Amarah, they were badly outmatched.In congress with the Ordo Xenos, the Synod Militaris Tempestus has concluded that except for the call of a full-fledged Imperial Crusade -- which estimates indicate will be unavailable before the passage of three to five solar decades -- the Orpheus Sector cannot be saved. Thus, Segmentum authorities petitioned the High Lords of Terra for permission to enact an Exterminatus Firebreak Protocol which would see the Imperium evacuate the remaining worlds of the Orpheus Sector and retreat to the Eurydice Sector, whose borders were to be heavily fortified.These decisions were formally ratified in 999.M41 by a special Edict Imperialis of the High Lords of Terra, which has since then become known as the Orphean Decree. The Orphean Decree effectively put an end to the existence of the Orpheus Sector as a Sector Imperialis, its rights and tithes annulled and its historical records sealed except for the use of the Inquisition's Chamber Mori. Under the overall guidance of the Ordo Xenos, the remaining worlds of the Orpheus Sector were declared Perdita upon pain of death, except for the worlds of Gorgon Quintus.The Gorgon Quintus System would serve as a rallying point and the headquarters of the Orphean Salvation Campaign, and the Fortress World of Lysmarchus, which was formally attached to the Eurydice Sector, as the new Imperial bulwark destined to hold the Necrons at bay. The Orphean Salvation Campaign would try to hold off the Necron advance as long as possible, with many of its regiments being granted the honour of martyrdom in combat, while strategically important assets were to be retrieved so that they might continue to benefit the Imperium.Much of the new campaign's efforts were concentrated on dismantling and relocating the precious installations of the Forge World of Myre in the Orphean Capitoline Sub-sector to the colony world of Jirgath whose domains and people had been ceded to the Adeptus Mechanicus in compensation for the loss of their planet. On many other worlds, mineral wealth and equipment, including military assets such as troops, weapons and ammunition, were stripped, often leaving the population bereft of any protection before the Necrons or the advance of the Forces of Chaos.Rearmed and repaired, the Minotaurs Chapter and the remains of Battlefleet Orpheus then enacted the ultimate sanction of the Exterminatus on more than twelve major worlds in the former Orpheus Sector, scorching the earth in order to further slow down the Necron advance.Several regiments, by now veterans from the war against the Necrons such as the Death Korps' 134th Heavy Infantry Regiment, were purposefully preserved and placed under the orders of the Ordo Xenos' Eurydice Conclave to man the Imperial fortresses being erected across the newly-created stellar no-man's land that had once been a sector of the Imperium.