Sotha was a far-flung world close to the edge of the galaxy's Eastern Fringe discovered during the Great Crusade in 882.M30 by the Imperial Expeditionary Fleets of the Ultramarines Legion. Sotha would later serve as the Chapter homeworld of the Scythes of the Emperor, a Loyalist Space Marine Chapter, a Successor Chapter of the Ultramarines. The Scythes of the Emperor, along with their allies, the Lamenters Chapter, were virtually destroyed during the invasion of the Imperium of Man by the Tyranids' Hive Fleet Kraken in 992.M41.
The Great Crusade
Sotha was a far-flung world close to the edge of the galaxy's Eastern Fringe, almost at the limits of both the fiefdom of the Five Hundred Worlds of Ultramar and the span of all Imperial territory. It was one of the few Terra-comparable ecosystems discovered so far out in the galactic East during the Great Crusade. It possessed living oceans and densely forested, mountainous landmasses. There were lower-level animal-forms, including avians and insects. Curiously, there were no higher forms of life, nor any obvious trace of attempted xenos visitation or colonisation. Primarch Roboute Guilliman and the Expedition Fleets of Ultramar had always considered the world a particular curiousity, for it had not been settled during the outward human expansion of the Age of Technology. There was no evidence that any human presence had reached Sotha, not even a colony that had been established and then died out.
Not long after its initial discovery, Imperial surveyors discovered something amazing beneath Mount Pharos, the tallest of all the peaks in the planet's majestic mountain ranges. A survey mission conducted by both archaeologists and xenoculturists discovered a massive aperture constructed by an unknown xenos species. Known as the Pharos, the interior spaces of the large archaic device were cut from the mountain's living rock by processes that no one had been able to explain. Plans for full colonisation by the people of Ultramar were put on hold. A small agri-colony was approved instead, to be based on Sotha in support of the Imperial survey to Mount Pharos. A dedicated unit of Ultramarines, the 199th Company, was assigned to Sotha as permanent protection, and the world was given the classification "restricted".
The Horus Heresy
Barabas Dantioch, a former Warsmith of the traitorous Iron Warriors, who remained staunchly loyal to the Emperor, was recruited by Roboute Guilliman for his skills in the arts of siegecraft. Dantioch and his Loyalist compatriots of the IVth Legion managed to arrive in the Realm of Ultramar before the Battle of Calth, was initiated by the treacherous Word Bearers Legion. During the Traitors' assault, the Dark Apostle Erebus managed to complete a blasphemous ritual on Calth's surface, which summoned a Ruinstorm to the galaxy's Eastern Fringe -- a monstrous Warp Storm larger and more destructive than anything space-faring humanity had witnessed since the days of the Age of Strife. It would split the void asunder, dividing the galaxy in two and rendering vast tracts of the Imperium impassable for centuries. The Five Hundred Worlds was rendered unnavigable except for the most high-risk enterprises. Imperial trade and communication in the region collapsed. Ultramar, as a single and admirable area of Imperial governance, was ruined. The Ruinstorm would also isolate and trap those Loyalist forces caught behind it like the Ultramarines, preventing them from coordinating their efforts and supporting one another as the Traitor Legions moved towards Terra.
Dantioch had supposed that he would be employed in fortifying the physical defences of Macragge and other key worlds of Ultramar, for this was his forte. Then Roboute Guilliman had revealed to him the long-sequestered mysteries of Sotha, and Dantioch had realised that the survival of a pocket empire like Ultramar lay less in fortifying its physical defences and far, far more in strengthening its function and operation. Dantioch spent over nine solar months unlocking Sotha's mysteries and activating the planet's deep-time secrets. Dantioch agreed absolutely with the Ultramarines Primarch's assessment -- Sotha offered a way in which the Loyalists might overcome the Ruinstorm, rather than batten down against its wrath.
Dantioch and the Ultramarines descended into the vast chambers of the Pharos on pre-fabricated walkways of STC design to provide platforms, ladders, stairs and bridges that would allow humans to traverse and explore the almost endless interior of the Pharos. During their explorations they discovered a central chamber, later known as Primary Location Alpha, which Dantioch was convinced was the centre of the entire mechanism. Dantioch took to referring to it in his notes as the "tuning stage" or the "sounding board". He had been fairly confident that he understood the function of the Pharos even from the data he had studied before his arrival on Sotha. The Pharos was part of an ancient interstellar navigation system, both a beacon and route-finder, and it also permitted instantaneous communication across unimaginable distances. Unlike Imperial Warp technology that used the Immaterium to by-pass realspace, the quantum function of the Pharos once allowed for site-to-site teleportation, perhaps through a network of gateways. Its fundamental function lay not with psychic energy, but with empathic power.
Dantioch also believed that other way stations like the Pharos still existed, or once did, on other worlds throughout the galaxy. It was not one, single beacon like the Astronomican. Dantioch believed the Pharos and other stations like it were once used to create a network of navigational pathways between stars, as opposed to a single, range-finding point the way the Astronomican did. The Pharos was more like a lantern than a beacon. The Pharos could be tuned and pointed, illuminating a site or location for the benefit of range-finding. Though Roboute Guilliman was loathe to use xenos technology, Ultramar had to be held together, and to rebuild the Five Hundred Words, the Loyalists had to restore communication and travel links by piercing and banishing the current age of darkness. Utilising its strange abilities, Dantioch was able to illuminate Macragge, lighting it up as a bright spot that was visible throughout realspace and the Warp, despite the effects of the Ruinstorm, providing a directional beacon for navigation in the absence of the Astronomican.
Following the events of the Horus Heresy, it is not known whether or not the Pharos still existed in the late 41st Millennium or whether the Scythes of the Emperor Chapter who came to hold Sotha as their fief, was even aware of its existence.
The Fall of Sotha
The Scythes of the Emperor (sometimes referred to as the Emperor's Scythes) was designated Space Marine Chapter 874, and was Founded approximately in the years 500-600.M41 during the 25th Founding. This made the Scythes one of the Imperium's relatively newest brotherhoods of Space Marines. The Scythes established a fortress-monastery upon their newly designated Chapter homeworld of Sotha. From this base of operations, near the region of space known as the Damocles Gulf in the Segmentum Ultima, the Chapter took upon themselves the duty of policing and safeguarding many of the nearby mining and manufactorum settlements.
Over 300 standard years after the assault of Hive Fleet Behemoth, the first of many Hive Fleets of the dreaded Tyranids) upon the Eastern Fringes of the galaxy, the Emperor's Tarot began to tell of foul portents ten standard years before the arrival of Hive Fleet Kraken in 992.M41. Among the planets overwhelmed by the locust-tide of the Kraken was the Scythes of the Emperor's homeworld of Sotha. Even for a well-defended Chapter planet, there was little hope against such vast numbers of xenos and their remorseless hunger. With devastating losses to the Chapter fleet, the Scythes were driven back to their fortress-monastery, which quickly came under siege by the Tyranids. Thousands of Tyranid bio-forms landed on the planet, and the Scythes prepared to make their stand at their fortress-monastery in order to give as much time as possible for the civilian population of Sotha to evacuate. Before the planet and the Scythes' fortress-monastery were completely overrun, the Scythes managed a breakout from the doomed world, falling back to regroup in the nearby Miral System. Sotha, along with so many other planets in the path of the inexorable advance of Hive Fleet Kraken, was reduced to the barren state of an asteroid by the Tyranid swarms. Two hundred Space Marines from the Chapter broke through the Tyranid assault but every mortal Chapter Serf and servant was lost. With much of the region overwhelmed by the Tyranids, there was nowhere for these brave Astartes to go beyond the claws of the Kraken. Sotha was completely consumed by the Tyranids and eventually was reduced to nothing more than mere rubble floating in the void of space.
- White Dwarf 306 (UK), "Index Astartes: Purge the Alien", pg. 52
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