Though now a footnote in history, the Rangdan Xenocides were a massive series of campaigns fought for Humanity's survival. Over the campaigns 80,000 Astartes and millions of Imperial Army gave their lives to hold back the Rangda and their slave cohorts.
First Rangdan Xenocide
The wars began in the 839.M30 when the vicious Rangdan species of Xenos invaded the frontiers of the nascent Imperium. They were first encountered by the Imperium at Advex-Mors and engaged by the First Legion, which lost 5,000 Battle-Brothers of 4 months. However this was later discovered to be but a small outpost for the Rangda. However the sudden apperance of Imperial forces stayed the Rangda's invasion for several decades.
Much of what happened during this conflict is unclear, but what can be said is that with the breaking of the Labyrinth of Night by the Emperor, the threat was at last stymied. What remained was for the Rangdan taint to be purged in a subsequent decade-long series of purges that left entire human inhabited sectors lifeless to ensure what was hoped to be a final victory. The Rangdan were vicious foes and even their ships were capable of causing heavier losses than they endured against the Imperium in 1 on 1 combat.
Second Rangdan Xenocide
In 862.M30 the Rangda invaded from the galactic north and east, inflicting losses on the Imperium on a scale that would not be seen until the Horus Heresy. Whole Expeditionary fleets went to their deaths without a single survivor, worlds were laid waste, dozens of Titan Legions were obliterated, and entire Space Marine Legions were said to be lost to the Imperium. It was only by the efforts of the V Legion and XIX Legion that the tide was delayed long enough to allow Imperial forces to rally and make their stand at the Forge World of Xana. At Xana the Vth and XIXth Legions fought a bitter holding action for 8 months at a cost of 3,000 Astartes and many hundreds of thousands of Mechanicum troops. The siege was eventually broken by the arrival of the Dark Angels and Death Guard. What would follow was more than two decades of war and millions upon millions of deaths that saw 19 systems laid to waste. Contingents from nine separate Legions became embroiled in the war with more than 300,000 Space Marines and 3 Primarchs including Lion El'Jonson being deployed during the climatic assault on Taxal.
In 881.M30, an incident known as the Majind Torc Transgression took place when a Basemekanic Barq broke the Imperial blockade of the galactic northeast to make impact at Majind. The Death Guard was mobilized to decimate the activated Macrobeest within by unknown means. Only the quick thinking intervention of the VIth Legion prevented disaster.
The last known battle of the Second Rangdan War was in 882.M30 when a battered Rangdan fleet was encountered and slaughtered. The worlds tainted by the Rangdan beyond recovery were abandoned and the surviving veterans sworn to silence or elimination.
Third Rangdan Xenocide
The most well-known stage of the conflict was the Third Rangdan Xenocide in the 890s.M30. This campaign was led by the Dark Angels and Space Wolves under their Primarchs Lion El'Jonson and Leman Russ. During the campaign, the Astartes prevented the total destruction of the northern Imperium but suffered devastating casualties, losing 50,000 Battle-Brothers. The losses the Dark Angels endured eventually contributed in them losing their status as the largest legion to the Ultramarines.
During the later stages of the war a member of the XXth Legion identifying itself as Alpharius but admitting their primarch had not yet been discovered came before the Lion. This "Alpharius" offered aid to the Primarch against the Rangdan in hopes that the Dark Angels would maintain their prominence and thus one day The Lion would be made Warmaster. The Lion at this time did not even know of the title Warmaster, but still secretly believed that such a title may one day be likely bestowed by one of the Primarch's by the Emperor. Alpharius stated that the XXth Legion would prefer The Lion be Warmaster over someone like Roboute Guilliman, as he was not so different from them in their views of war and secrecy. It is not ultimately known if The Lion accepted Alpharius' help or not, though the Rangdan were destroyed shortly after.
The Rangdan were chased back to their homeworlds, which were eventually discovered by scouting White Scars. This was no war but a campaign of extermination in often one-sided battles. Neither Russ or the Lion held any illusions of chivalry and sought to annihilate the Rangda completely. On their homeworld of Rangda the xenos were laid bare at least and their hideous cities were reduced to nothing.
- 1: The Horus Heresy Book Seven pgs. 81–82
- 2: The Horus Heresy Book Five pg. 96
- 3: The Horus Heresy Book Three pg. 82
- 4: Scions of the Emperor (Anthology) - First Legion
- 5: The Horus Heresy Book Eight pg.16
- 6: The Horus Heresy Book Nine pg.90-91