Discovery and Early History
Located by the Empire’s explorator fleets relatively early during the great crusade, the Pythos system was located near several major stable warp corridors and was deemed to be a suitable location to establish a resupply base for the fleets of the great crusade.
The system’s fourth planet, Pythos IV was found to have a habitable biosphere and was rapidly transformed into an agriworld with facilities to resupply the Emperor’s forces with all the war materials they would need to unify the galaxy. Pythos IV was discovered to be an eldar maiden world about fifty years after colonization when forces from an unknown craft world attacked imperial forces without warning. Fortunately for the imperium, several ships of the XVIII legion were resupplying in orbit, the embarked space marines rapidly deployed from orbit and drove off the xenos in a short but brutal campaign.
Afterwards, Pythos IV was permanently garrisoned by a small force of space marines of the IV legion to discourage further eldar raids. The planet’s defenses were immediately strengthened with the installation of several shield generators on the planet and the construction of a formidable defense battery on Pythos IV’s moon. It’s security thus ensured, Pythos IV continued to prosper throughout the rest of the great crusade, its orbital docks becoming a major waypoint of the emerging Segmentium Tempusts.
Loss during the Horus Heresy
All that changed during the Horus Heresy. During the traitor’s advance on Terra, Horus dispatched forces to capture several systems both to resupply his forces and to deny critical materials to the Emperor’s forces. Securing Pythos IV and its large stockpiles of materials fell to the Word Bearers. In his arrogance, Lorgar dispatched only a tolken force, assuming that the Iron Warriors garrisoning the planet would follow their primarch into forsaking the Emperor. The approaching fleet soon learned that was not the case when several of its lead ships were obliterated by the planet’s defenses. Over the course of several weeks, the Word Bearers were able to destroy the orbital defense platforms ringing the planet at great cost, but the surviving ships could not bring enough firepower to penetrate Pythos IV’s shields.
Enraged by the defender’s defiance, Lorgar withdrew his forces and summoned a warp storm of tremendous power to seal off the system, declaring that if Horus could not control the Pythos system, no one would. Thus Pythos IV faded from memory as the terrible events of the Horus Heresy ran their course.
Pythos IV is Rediscovered
The Pythos system was rediscovered in M41.980 by the rogue trader Van Buran when his fleet found itself blown off course by a warp squall. Emerging in the abandoned system, the rogue trader encountered the wreckage of an ancient battle throughout the system. Pythos IV appeared to be untouched, though no signs of inhabitants on the planed were found. While the planet’s moon was found to be wrapped in an impenetrable shield, landings were successfully made at the various starports on Pythos IV. Planet side exploration found massive stockpiles of war supplies and other advanced technology waiting to be claimed.
Van Buran likely would have kept his discovery a secret to exploit for his own gain had misfortune not befallen. The rogue trader’s fleet had been infiltrated by a brood of genestealers which had quietly infected the crews of several ships.
The genestealers attempted to seize control, which resulted in a pitched battle between those ships were not taken over. Van Buran’s personal astropath was able to send a frantic distress call before being torn apart by several tyranid monstrosities. In the end, all of the ships were lost either to the guns of their former comrades or when their plasma drives were overloaded. Some crew members managed to escape to Pythos IV, but they were eventually hunted down by the genestealers that managed to make planet fall.