ca. 830.M30 III Legion Gene-Seed Crisis - Coming within a solar year of their great moment of triumph fighting at the Emperor's side at Proxima, the III Legion suffered the catastrophic loss of nearly their entire gene-seed stock. This would prove a turning point that was to forever alter the Legion's future. When the III Legion's gene-seed reserve was despatched to Luna for establishment there, it is not quite clear what exactly happened next. Some claim that elements of the Selenite gene-cults still resistant to the Imperium hijacked a Defence Laser and destroyed the voidship carrying the gene-seed, while conflicting accounts maintain that the ship lost control and crashed as it was attempting to dock, whilst others claim that it simply vanished. The loss of the III Legion's gene-seed reserve was a severe blow, but it would not have endangered the Legion's survival if a second calamity had not occurred in quick succession. It was soon discovered that a fast-acting viral blight had suddenly infected several of the gene-seed vaults on Terra, its cause and origin unknown. Feverishly, the Magi Biologis of the Mechanicum sought to hold the pathogen, soon called simply "the Blight," in check as its progress threatened to wipe out in a matter of solar hours what had taken a standard century to build, but the doubtlessly artificial -- and many believed xenos -- infection defied treatment. It was only the intervention of the Emperor's own peerless genius that was to purge the taint. While many Legions suffered losses from this attack from an unknown quarter, the blight was found to have destroyed the gene-seed of the III Legion in its entirety.
ca. 830.M30 The "Ghost Legion" - Anomalous Legiones Astartes activity is first reported. There are only a few sparse but suggestive fragments -- anomalous records of unknown Legiones Astartes units carrying out targeted strikes, abductions and assassinations, both on Terra and beyond, and reports of Space Marine units answering to no known masters or Legion allegiance passing through war zones on high-priority missions and under the writ of unassailable clearance codes which broached no question. These mysterious elements are attributed to the mysterious "Ghost Legion."
830.M31 Discovery of Fulgrim - The Emperor came to the industrial Mining World of Chemos and was reunited with His lost son Fulgrim, who had rebuilt his ravaged and resource-poor homeworld. Upon their first meeting, Fulgrim recognised the Emperor for who He truly was. Fulgrim bent his knee and offered his sword in eternal servitude. Pleased, the Emperor brought Fulgrim into the Imperial fold, and not long after, gave him command of the III Legion. The first speech Fulgrim gave to the III Legion moves the Emperor to rename them the Emperor's Children -- an extraodinary honour that Fulgrim swears to uphold by striving for perfection in all things.
ca. 830s.M30 Praxil Rebellion - When the worlds of the Praxil System were first discovered, the Imperium was pleased by the prospect of adding them to the Emperor's domain. Though bringing Praxil into Imperial Compliance would bring the Imperium great renown, this formidable human civilisation refused to bend the knee to the light of the Imperial Truth, and instead was prepared to fight to maintain its independence. Praxil's warfleet was formidable, and managed to push back the initial invasion of the Imperial Expeditionary Fleet sent to carry out the conquest. The Imperium wanted Praxil's wealth and resources to harness to the needs of the Great Crusade, and so the securing of Praxil fell to an army group-sized force of the Emperor's Children, supported by selected elements of the Imperial Army and the forces of the Mechanicum. But the initial campaign did not go well, as the Imperial forces sustained severe casualties and faced opposition at every turn, despite changing their tactics. Too prideful to ask for help, the War Council of Terra sent a force of Blood Angels and Imperial Fists to assist the beleaguered Imperial forces. Despite his misgivings and slight to his personal honour, the Lord Commander of the III Legion contingent accepted his cousin Legions' assistance and immediately drew up plans for prosecuting the second offensive against the Praxil. With their combined strength, the Imperial forces launched a successful second offensive against Praxil that soon saw an Imperial victory.
ca. 800s.M30 Defence of Tranquility - The Defence of Tranquility was a protracted and vicious engagement fought by the Emperor's Children on the periphery of the Dalinite Nebula region during the early phase of the Great Crusade's progress into the galactic east. Of particular interest to the Imperium was the discovery of the Dalinite Gates, which were part of the mysterious series of Warp Gates scattered across the stars, which could greatly increase the ability of the Imperium's fleets to reach new targets and expand the range of the Emperor's forces. A Cohort barely numbering 500 warriors of the Emperor's Children was given the important role of securing the world of Tranquility on the trailing edge of the Imperial advance. The world was utterly worthless except that a Warp Gate, designated the Tranquility Gate, hung in high orbit above the planet's pole and a forward Imperial navigation and signal relay had been constructed there. Without warning, a larger xenos fleet exited the Warp Gate, which proceeded to mount a ground assault on the planet's surface. The Imperial warships executed a rapid, desperate counterattack, which caused the xenos fleet to flee back through the Warp Gate, and leaving their ground forces to be annihilated by the vengeful Emperor's Children.
ca. 800s.M30 Extinction of the Katara - The xenocide of the alien Katara was a brutal campaign of extermination carried out against this insular Abhuman civilisation that had evolved in the Kenuit System. Initially offering no resistance, matters only deteriorated when the Katara were asked directly to formally surrender to the Imperium. Soon a lone Kataran warship arrived and destroyed the Light Cruiser Locrian before sustaining damage itself and withdrawing. So provoked, acting Lieutenant Commander Abdemon of the Emperor's Children ordered the invasion of the largest Kataran city-complex. The Katara's diplomatic representatives came forward again, requesting to meet in a truce. He made the proposal that the conflict should be decided by a lone champion from each faction. Lieutenant Commander Abdemon agreed and said that he would enter the field as the Imperium's champion. Both combatants fought a brilliant, long drawn-out and bloody duel. The Imperial champion got under the alien's guard and delivered the killing blow. With their champion defeated, the Kataran representatives ordered that all should know that their people had been defeated by an enemy of equal honour but superior arts. The order given, the Kataran leaders fell on their own swords before the Emperor's Children. Across all their domains every member of the Katara followed their leaders in death and the Kataran cities became massive tombs. Showing respect for their fallen foes, the Emperor's Children departed the Kenuit System, leaving the world of Katara as a Mortuary World, a monument to its people's valour and self-sacrifice.
ca. 800s.M30 Castigation of Terentius - When the forces of the Great Crusade first entered the Ordoni Cluster, they encountered the formidable warlord Vatale Gerron Terentius. Observing the forces arrayed against him, Terentius was forced to take the path of survival and surrendered to the Imperium. For the next five solar decades he rose in power and reputation, conquering worlds around the Halo Stars in the name of the Emperor. At the height of his powers, he had the ear of Malcador the Sigillite, the Regent of Terra, and the countenance of several of the Primarchs. When he finally turned against the Imperium, many were shocked. He began a contra-Crusade to conquer already-Compliant worlds to add to his pocket empire. The Imperium responded by sending Horus and his Luna Wolves Legion to not only break the Renegade but to demonstrate to any others who harboured similar ideas within the Imperial forces the inevitability of a betrayer's defeat. Heavy support from the Night Lords, Iron Hands and the Alpha Legion joined the might of the Luna Wolves. Soon the rebel forces were fragmented, driven by tales of culled worlds. At the height of the campaign, Horus himself, with a cadre of 50 elite Justaerin Terminators, teleported aboard the bridge of Terentius' flagship, where the Luna Wolves' Commander slew the unrepentant traitor with his Talon. The Night Lords decimated every world within Terentius' rebel empire. The power of the Iron Hands and elements of the Ordo Reductor were brought to bear on every structure on Terentius' bastion worlds. Soon the rebels of his realm were slaughtered, their cities smashed to dust, and his homeworld's very air laced with toxins. Once the castigation was complete, Horus sent the gold-dipped skull of Terentius to Terra with the later ironic warning carried on the lips of the messenger who bore it, "So perish all traitors."
832.M30 Discovery of Vulkan - The Primarch Vulkan was raised by a blacksmith on the fiery, volcanic world of Nocturne, becoming a giant hero amongst his people. The Emperor arrived upon Nocturne and reunited with His lost son, who only agreed to serve the Emperor after competing in a difficult challenge to slay the largest salamander -- a large drake-like creature native to Nocturne. During the contest, Vulkan's life ended up in jeopardy, and though the Emperor had obtained a larger prize, He sacrificed His trophy in order to save His gene-son's life. Humbled by the stranger's deed of self-sacrifice, Vulkan bent his knee to the Master of Mankind. It is believed he served with the Emperor for some time before he finally took command of the XVIII Legion -- the Salamanders.