|Map||Basic Data||Planetary Image|
|Class:||Previously Civilised World, Adeptus Astartes Homeworld, Tomb World[9c]. Now Dead World though being restored[9b]|
|Tithe Grade:||Previously Aptus Non, now n/a|
The Great Crusade
In spite of an ideal ecosphere, there were no initial signs of previous human or xenos occupation, but after initial exploration of Mount Pharos an ancient structure of alien origin was discovered. Access to the entire world was restricted by order of the primarch Roboute Guilliman, with only a small agricultural colony to support the ongoing archaeological survey mission. The 199th Company of the Ultramarines was established as an '‘Aegida’' (shield-company) and left to garrison the world.[5b]
The company took on a badge of a scythe to represent the assistance of the local agricultural workers in clearing the vegetation.[5c]
The Horus Heresy
At the height of the Horus Heresy, at Guilliman’s command the renegade warsmith Barabas Dantioch of the Iron Warriors had been sent to Sotha to uncover the secrets of the Pharos, and succeeded in opening up instantaneous communication channels with distant Macragge. The Pharos was found to be an empathic device of ancient xenos construction, and provided a directional beacon for navigation in the absence of the Astronomican. [5d]
The planet was designated by Sevatar as a rendezvous point for the Night Lords fleet elements after the disastrous conclusion of the Thramas Crusade. It is unclear whether or not he knew of the significance that the planet had attained, before giving this order. Sothan rendezvous point was used by Gendor Skraivok commanding 45th Company aboard strike cruiser Umber Prince. Two other Night Lords vessels, the Domninus Noctem and Shadow Blow used this rendezvous point but left it after completing repairs. Some time later, smaller Night Lords fleet under captain Krukesh the Pale, commander of 103rd Company and member of the Kyroptera arrived and Krukesh inducted Skraivok and the Umber Prince into his order of battle. Night Lord forces under Krukesh's command launched attack on Sotha System that resulted into Battle of Sotha. 
In the aftermath of the battle, the emblem of the 199th Company of the Ultramarines was awarded by Roboute Guilliman with two crossed scythes as a symbol of their victory. After the formation of the Codex Astartes, the 199th continued to oversee Sotha as the Scythes of the Emperor, making the world their base of operations.
The Second Tyrannic War
In the last decade of M41, reports began to reach Sotha of unrest and rebellion spreading along the Eastern Fringe. Chapter Master Thorcyra sent Captain Cassios and the Scythes' Fifth Company to crush any uprising before it could begin before himself heading north into the Saphir Cluster. After a year, garbled communications reached Sotha from the Fifth of a widespread xenos incursion into the galaxy — this turned out to be the work of Genestealer Cultists on behalf of the Tyranids of Hive Fleet Kraken.
A general recall was issued, summoning every single battle-brother of the Chapter back to Sotha to aid in the defence of their home world. Secretly, the best and the brightest of the youth of Sotha were evacuated, as it was already suspected that it was too late to halt the alien menace and new recruits would soon be required to replace losses and rebuild the Chapter.
The invasion began with a single Hive Ship which appeared at the edge of the system. Sergeant Remas led a boarding mission to halt the ship but barely escaped with his life. Soon afterwards, a rain of Mycetic Spores brought billions of Tyranid creatures to the surface. They swarmed over the defensive barricades and the Scythes of the Emperor were decimated. The survivors were evacuated by the Chapter's remaining Thunderhawks, and fled to the death world of Miral to rendezvous with the returning Chapter Master Thorcyra.
Sotha was completely consumed by the Tyranids, and every single human serf and Chapter servant was lost. Later, Thorcyra's successor Thrasius described Sotha as having been reduced to "mere rubble in space".
During the Age of the Dark Imperium Belisarius Cawl led an expedition to Sotha to study the Pharos along with the Scythes of the Emperor and Decimus Felix.[9d] However the Scythes Chapter Serfs were infiltrated by the same Genestealer Cultists that had previously ravaged Sotha. During the fighting,, Scythes Chapter Master Thrasius died slaying a Genestealer Patriarch while the rest of the Scythes Firstborn perished.[9a] Meanwhile the Pharos collapsed, and Cawl was forced to flee the world after the C'tan Zarhulash escaped from its bindings and the Pharos was destroyed. Cawl originally had intended to rebuild the world, though he stated this would take some time.[9b]
- Mount Pharos - atop of which formerly sat the Fortress-Monastery of the Scythes of the Emperor[9e]
- Blackrock Mountains[9e]
- Aegida - Space Station and Fortress-Monastery of the Scythes of the Emperor.[9b]
Flora and Fauna
- Commander Cassios
- Reclusiarch Hornindal
- Sergeant Tiresias
- Neophyte Pasan
- Serf-sergeant Milus Ogden
- 1: Orphans of the Kraken (Short Story)
- 2: The Shadow of the Beast (Short Story)
- 3: White Dwarf 306 (UK), pg. 52 Index Astartes: Purge the Alien
- 4: Prince of Crows (Novella),[Needs Citation]
- 5: The Unremembered Empire (Novel)
- 6: The Blood of Sotha (Short Story)
- 7: A Safe and Shadowed Place (Short Story) — Death and Defiance (Anthology)
- 8: Pharos (Novel), [Needs Citation]
- 9: Belisarius Cawl: The Great Work (Novel)
- White Dwarf 218 (UK), pg. 80 The Coming of the Great Devourer