The Raven Guard were the smallest of all the legions during the Great Crusade. The Horus Heresy would nearly obliterate them.
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The Raven Guard legion was one of the smallest legions during the Great Crusade, numbering 80,000 Astartes as well as an Imperial Army Regiment known as the Therion Cohort attached to the legion’s expeditionary force. As a legion they were a fierce enemy for anyone who opposed the Imperium of Man, using time honored tactics of guerrilla warfare which Corax himself had learnt during the Revolution he himself had commanded to free his people from the merciless slavery forced upon them by the Tech Guilds of Kiavahr. Extremely efficient and trained, the Raven Guard would engage in acts of mass sabotage along with infiltration, blink-of-an-eye Strikes, and expert covert operations, all of which they had perfected into what would look like ease to any other warrior.
The Raven Guard were one of seven legions to be sent to the Istvaan system (Others present were the Iron Hands, Salamanders, Alpha Legion, Iron Warriors, Night Lords and Word Bearers) to quell a rebellion lead by the former Warmaster, Horus – Primarch of the Sons of Horus Legion (Formerly the Luna Wolves). Horus and his other three traitor primarchs (Fulgrim, Angron and Mortarion) had entrenched themselves on the planet of Istvaan V, and lay in wait for the Loyalist forces to land and engage. The fighting once joined was fierce and hot-blooded, brother versus brother, and no quarter was given on either side. Mid way into the fighting, Horus and his allies retreated back into their fortifications for no reason that could be grasped by the loyalist factions.
The Raven Guard were in the thick of the fighting from the start, though out of their element due to the lack of tactical planning and the close-up-and-personal combat spreading like wildfire across the plains of Istvaan V. They fought both with as much honour and as much skill as any other legion would in the circumstances. When the traitors made a surprise withdrawal back to their fortifications, the Raven Guard used this cease in the fighting to regroup and re-arm. However, when they neared the “loyalist” defenses (which were tenfold reinforced by the expert siege engineers of the Iron Warriors legion under their Primarch Perturabo’s direction, they were fired upon by the very guns meant to protect them. Hundreds were gunned down in the first few minutes of the betrayal, before they even realized that there were traitors in there midst.
Four of the seven loyalist legions sent to Istvaan V had thrown off the colors and pretenses of the Imperium, and set about playing out a totally new performance (hatched from long before Istvaan). The Iron Warriors, Night Lords, Alpha Legion, and Word Bearers turned on their brethren in a bloody thunderstorm of bolters and blades, decimating their numbers in a multitude of seemingly never ending skirmishes and drudging battles for ground that cost lives for every metre gained or lost. Corax and his legion were reduced from their mighty 80,000 warriors to a meager 3,000 battle hardened veterans.
Himself by now a brooding vengeful demigod, wielding a whip in place of his normal customary left set of talons which were lost in a rage fueled duel with the traitorous Primarch Lorgar, which would have ended in Lorgar’s death had Konrad Curze, Primarch of the Night Lords (also known as the Night Haunter) not intervened and shattered it with a swipe of his own claws.
Evacuation came in the form of a single battle barge “Avenger”, captained by Commander Branne Nev, a captain originally stationed on Deliverance as a garrison commander, with him came the battered remains of the Therion Cohort normally serving with the legion under Praefactor Marcus Valerius who ironically brought Isstvan V into compliance with Corax the first time. Unbeknownst to both sides, Corax’s only narrowly escaped death at the hands of Angron and his World Eaters thanks to the machinations of the Alpha Legion, whose own Primarch Alpharius had greater plans regarding the Raven Guard.
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