Endymion Prime is a blighted Industrial World located in the Endymion Cluster within the Maelstrom Zone of the Segmentum Ultima. During the Badab War the brutal and savage Carcharodons Chapter of Space Marines were unleashed upon the worlds of the Endymion Cluster in order to defeat the Secessionist Mantis Warriors Chapter and protect the flank of the Loyalists as they launched a full invasion of the Badab Sector. The Carcharodons systematically annihilated planets in the Cluster known to have harboured the Mantis Warriors and forced the Secessionist Chapter to stop using their hit-and-run tactics and concentrate their forces in defence of these worlds.

This strategy spared the Carcharodons from having to pursue the Mantis Warriors across the Cluster to worlds where their foes held the advantage of support from the population and local knowledge. Each battle forced the Mantis Warriors to come to the aid of the beleaguered worlds, destroying their ability to affect the broader outcome of the war.

Worn down and scattered, the Mantis Warriors ceased to exist as an effective fighting force, though the Carcharodons' victory came at a great price. Unfortunately for the ravaged people of the Endymion Cluster, this would not be the only time when calamity was visited upon their doomed worlds, for the Carcharodons would return in later years to enact a final act of savagery against them in the aftermath of the conflict.


As with many of the settled worlds in the Endymion Cluster, the human habitation of Endymion Prime can be traced back at least to the late 34th Millennium, with it reaching its apotheosis during the 38th Millennium as the region's only industrial sub-Hive World, although it never attained the scale of production and population of either Cygnax or Badab Primaris elsewhere in the Maelstrom Zone. Subject to privation and attack from pirates, xenos and Renegades owing to its proximity to the Maelstrom on numerous occasions, the planet suffered an economic collapse and overall decline during the 39th Millennium when its primary natural resources were exhausted. Its population and industrial capacity then proceeded to shrink over the intervening centuries until Endymion Prime reached its current parlous state.

Endymion Cluster Map

Departmento Cartographicae Map of the Endymion Cluster

By 910.M41, during the sector-wide insurrection against the Imperium known as the Badab War, the Loyalist Magister Militant or supreme commander, Carab Culln of the Red Scorpions Chapter, ordered the deployment of the savage Carcharodons Chapter to subdue the worlds of the Endymion Cluster to prove their worth. The Secessionist Mantis Warriors, the ancient protectors of the Cluster, guided by the potent divinatory powers of their Chief Librarian, Ahazra Redth, had held out against the Imperial assault by conducting a protracted and highly effective guerrilla war against the Loyalist forces. The Carcharodons descended upon the unsuspecting worlds of the Endymion Cluster with shocking fury, carrying out genocidal actions that destroyed whole planetary populations. This campaign of wanton terror and destruction destroyed the Mantis Warriors' ability to affect the larger outcome of the war on the Secessionist side and soon forced their final surrender on Endymion Prime so that they could save what remained of the peoples they had been sworn to protect. Appalled by the savage actions of their allies on behalf of the Loyalist cause, the Astartes of the Fire Angels withdrew their remaining contingents from the conflict and returned to their homeworld to rebuild their shattered Chapter.

In 913.M41, one year after the death of Badab Primaris and the fall of Lufgt Huron, the Mantis Warriors and the remaining Secessionist Chapters were put on trial before a specially convened Consistorial Court of their peers in the Adeptus Astartes. The Mantis Warriors lost all rights to their ancient demesne in the Endymion Cluster, with their goods and chattel given over to the Fire Hawks Chapter in perpetuity. To further compound their shame and punishment, the imprisoned remainder of the Mantis Warriors could only watch as a great swath of the Endymion Cluster's young males were forcibly culled by the Carcharodons, taken as potential Aspirants to replenish their losses in the war. They were set against each other in vicious gladiatorial contests so that only the strongest and most vicious candidates would emerge to undergo the transformation into Carcharodon Space Marines. Additionally, the Carcharodons discovered and ransacked many of the Mantis Warriors' secret bases and caches of wargear, particularly on Endymion Prime. After they had completed the cull and replenished their supplies and materiel, the Carcharodons' Chapter fleet departed the sector, headed on a vector through the Warp towards the edge of known space.

Departmento Cartographicae Planetary Database

The estimated population of Endymion Prime in 907.M41 was 1.1 billion indigenous human-Imperials and Abhumans.

  • Class: Tellurian (Rotational period: 18 standard hours, 0.9 G, 0.85 tm)
  • Tithe Grade: Exactus Minoris (Formerly higher previous to economic collapse in ca. M39)
  • Climate/Geography/Biosphere: Unstable planetary climate typified by sulphurous rain storms, hurricane winds and specifically tornadoes in polar latitudes. Planetary surface designated as "ash waste" with majority of population subsisting in dispersed communities throughout post-industrial "sprawl" areas, with demographic concentrations found near higher-functioning industrial zones.
  • Governmental Type: Feudal Dictatorship, numerous rival Houses of Nobility. Noble power-base rests on control of industrial areas and refining contracts.
  • Planetary Governor: None. Last incumbent, Duke Fultan Vualanti of House Vualanti, was executed by the Fire Angels Chapter on charges of treason against the Emperor; no replacement appointed.
  • Adepta Presence: Minor; local Adeptus Ministorum clergy, extant Administratum and Adeptus Arbites representation purged during the world's Secession from the Imperium.
  • Military: As of 907.M41, former Planetary Defence Forces (PDF) made up of the combined armsmen cadres of Endymion's noble house (equivalent to second line Imperial Guard regiments) who joined in the Secessionists' open revolt against the Imperium and principal forces engaged in heretical insurgency against Imperial rule. These forces were essentially wiped out by the Carcharodons' victory in the Endymion Cluster.


  • Imperial Armour Volume Ten - The Badab War - Part Two, pp. 14-15, 18-19, 69, 119
Community content is available under CC-BY-SA unless otherwise noted.