Raven Guard - Rebuilding a Legion: Consumed by the loss of over 75,000 of his Legion's Astartes, and obsessed with thoughts of revenge against Horus, Corax ordered his survivors to return to Terra, where he intended to ask the Emperor for help in rebuilding the Legion.Following a number of delays and setbacks, and despite the disagreement and displeasure of Rogal Dorn and Malcador the Sigillite, Corax psychically communed with the Emperor, who was devoting all His time battling Chaos within the Warp and what remained of the secret Imperial extension into the Webway in the aftermath of Magnus the Red's catastrophic psychic intrusion into the Imperial Palace.The Emperor revealed certain truths to Corax: the existence of the Imperial project to control portions of the Webway, the nature of Chaos, and the truth behind the outbreak of the so-called Heresy -- which in reality was an all-out campaign by the Chaos Gods to defeat the Emperor and enslave Mankind, using Horus and the Traitor Legions as their pawns.The Emperor decided to help Corax, and had another, astonishing revelation to make: the Primarch Project's genetic assets had not been destroyed, as everyone had thought, but still existed and were dormant -- including living samples of the original gene-stock the Emperor had used to create the 20 Primarchs.The Emperor, who offered no explanation as to why such facilities and gene-stock still existed, demanded only one thing: this genetic material could never be allowed to fall into the wrong hands.Accompanied by several Raven Guard squads, a contingent of Mechanicum specialists, and a number of Custodians to serve as the Emperor's "overseers," Corax managed to locate and enter the Emperor's well-protected gene-laboratories deep beneath the Imperial Palace in the Himalazian Mountains, after his strike force suffered a number of casualties.The original Primarch gene-stock and related technical information was secured, and Corax and his Raven Guard warriors returned to Deliverance to begin remaking the Legion.After several solar weeks of effort by Corax, Chief Apothecary Vincente Sixx, and Magos Genetor Nexin Orlandriaz, a breakthrough was achieved, and a new reservoir of stable Astartes gene-seed was extracted from the original Primarch DNA.The gene-seed was more pure than "normal" Raven Guard gene stock as it came from undiluted Primarch DNA before it was broken down to the 20 different recombinant strands that gave birth to the original Primarchs. It was implanted using an extremely accelerated development schedule within 500 Aspirants, with excellent results.The resulting Astartes, though lacking combat experience, were even more capable than typical Raven Guard Space Marines. They were assigned the name "Raptors," and placed under the overall command of Captain Branne, who served as the Legion's Master of Recruits.Following a baptism by fire in a successful attack against a Word Bearers intelligence outpost/listening station, the prospects for the reconstruction of the XIXth Legion looked bright indeed.The Alpha Legion had other plans. Patiently waiting until the Raven Guard had achieved the genetic breakthrough, they were fomenting rebellion among the old tech-guilds of Kiavahr, the Forge World that the moon of Deliverance circled, while assembling an Alpha Legion force nearby, and simultaneously misleading both their nominal allies among the other Traitor Legions and their supposed allies in the Cabal about their true purpose.With the help of Adepts from the Dark Mechanicum the Alpha Legion operatives within the Raven Guard contaminated the pure Primarch gene-stock held by the Raven Guard with a virus that was tainted with daemonic essence.The nature of the virus was unknown to the Alpha Legionaries until after the gene-stock had been contaminated, as their Dark Mechanicum allies had insisted the virus could be easily extracted once the original Primarch gene-stock came into their possession.The next cadre of 2,000 newborn Raven Guard Astartes was predictably a disaster. All manifested hideous Warp-related mutations after they were implanted with their gene-seed organs, and many had to be kept imprisoned. Corax announced that mutation or not, he considered them as much a part of the Raven Guard as the rest of his Astartes, and vowed to find a way to reverse the mutations.Ninety percent of the recruits who underwent the accelerated treatments were unable to hold a standard Space Marine Bolter, let alone fire it. Of 100 recruits, perhaps one would have a genome stable enough to become a true Space Marine.At the same time, the Alpha Legion's plans were reaching their climax. The Kiavahr rebellion was well under way, supported by the newly arrived Alpha Legion force, who were camouflaged as Raven Guard, bearing the XIXth Legion's badges, insignia, and armour.These tactics were only diversions intended to allow the Alpha Legion operatives already within the XIXth Legion to steal the Primarch gene-stock and to completely destroy the original Raven Guard gene-seed, crippling the Loyalist Legion.The first objective was successful: the original Primarch DNA and all information about it was secured by Omegon, who had been secretly on Kiavahr all the time, manipulating events as needed. Yet the destruction of the Raven Guard's existing gene-seed was prevented by the Raven Guard Mutants, who were tasked by the dying Chief Apothecary Vincente Sixx to save the future of the XIXth Legion.Corax subsequently allowed the Mutants who could fight to join the Legion's Raptor Squads. They participated with the rest of the Raven Guard, a small force of Imperial Fists, and the reconstituted Therion Cohort in the first counterattack against the Traitors, and the Raven Guard's successful campaign against the garrison of an Emperor's Children-held planet near the Kiavahr System.Unfortunately the attempt to rebuild the XIXth Legion's strength was now in ruins. With a heavy heart, Corax decided that his attempt to use a shortcut to refill his Legion's ranks had been a mistake.He determined that the XIXth Legion would rebuild its ranks in the traditional way, slowly and painstakingly transforming human Aspirants into Space Marines over many standard years of genetic alteration and training. But the price would be that the Raven Guard would not be able to participate in a meaningful way in defending the Imperium against the Traitor Legions.This did not mean, however, that the Raven Guard would renounce taking part in the fight against Horus. Lacking the manpower to confront the Traitors in open battle, what remained of the Raven Guard would stalk the enemy's supply lines -- those worlds away from the front lines that were yet of strategic importance to the enemy.Over the following Terran years the Raven Guard would attack convoys, sabotage weapons deliveries, decimate planetary occupation forces, destroy orbital shipping yards, liberate worker camps and generally be a thorn in Horus' side.Every starship destroyed was one ship less to ferry troops to the inevitable Siege of Terra. Every weapons shipment destroyed was one shot less fired at the defenders of the Imperial Palace. Every planet liberated reduced the Traitors' manufacturing capabilities.This became the Ravens Guard's new mode of thinking -- if you could not strike at the enemy directly, hit them where it hurt.Following the later reorganisation of the Space Marine Legions into the Second Founding Chapters after the end of the Horus Heresy, the Raven Guard was left largely inoperable as a combat unit and was forced to spend solar decades recruiting new members and rebuilding itself.Finding itself woefully undermanned and under-equipped following the massacre on Istvaan V, the Raven Guard honed and perfected the use of covert small-unit, guerrilla tactics that utilised little fire support, armoured support or other heavy equipment that the Chapter and its Successors lacked.Even today, the Raven Guard's lack of Predators, Land Raiders, and the latest patterns of Power Armour reflect these conditions of the Chapter's past.