As is true of the Calixis Sector itself, the Expanse was untouched by the God-Emperor's Crusade many millennia ago and so it is a realm of fearsome xenos, treasures beyond imagining, heathen worlds of men, and the echoes of the ancient doom.
The Koronus Expanse's history is largely defined by the actions of the Rogue Traders who survived exploring it. However, its written history is full of apocryphal records and oral history regarding the region often comes from unreliable narrators as well, making a definitive recounting practically impossible.[2a]
The Calixis Sector was first charted during the Age of Apostasy by Solomon Haarlock, though fragmented naval records indicate that it was actually first charted by a prior Explorator fleet belonging to the Adeptus Mechanicus. The method of traversing the field of intense warp storm activity in what is now the Drusus Marches subsector is missing from both sets of data however, and so the Imperium designates the storm field as the farthest border of the Sector.[2a]
73 years after the Imperial Navy constructs the space station Port Wander near the storm field, a Rogue Trader named Purity Lathimon discovers "the Maw", a safe passage through the storms. However, rather than returning to the Expanse, she sells her knowledge on and departs Calixis, never to return. The Koronus Expanse is effectively declared part of the Calixis Sector by the High Lords of Terra.[2b]
Several worlds in the Expanse are colonised, while others were destroyed. The destruction largely caused by the Inquisitor Kobras Aquairre, who eventually leads his fleet into the Rifts of Hecaton and vanishes. Aeldari and other, even more mysterious xenos species are discovered in the Expanse.[2c]
The Koronus Expanse in the 41st Millennium is a scattered, partly explored region containing a few young colonies and vast natural wealth still barely explored. Rogue Traders vie with one another for known resources, heedless of lives lost in the pursuit of riches, while a tentative attempt at Imperial colonization follows in their wake.
Drawn by the flow of wealth, pirates and servants of Dark Gods have also slipped into the Expanse, eager to cast destruction upon the works of the God-Emperor's faithful, living by what they wrest from dead hands, while the Expanse itself holds many secrets and native inhabitants no less dangerous. Beyond these human conflicts lie truly dark and dangerous voids, rife with rumoured terrors, undiscovered stars, and worlds of man who have never known the God-Emperor. There are no defined warp-routes, no safe ways through the swirling empyrean. These regions hold the fearsome Ork, the treacherous Aeldari, and strange ruins that lie beneath the light of dying stars.
- Accursed Demesne[1b]
- Cinerus Maleficum[1b]
- Foundling Worlds[1b]
- Heathen Stars[1b]
- Ragged Worlds[1b]
- Rifts of Hecaton[1b]
- The Cauldron[1b]
- Unbeholden Reaches[1b]
- Winterscale's Realm[1b]
Rogue Traders and their involment
For centuries, Rogue Traders have braved great evils and the treacherous warp to venture into the Koronus Expanse, but their efforts have barely begun to uncover its secrets. Footholds have been built close to the few semi-stable warp routes into the area.
Here, resources-rich worlds are exploited, xenos ruins, trade envoys meet with heathen lords, and colonies are attempted upon sheltered worlds. This effort has been enough to shower wealth and fame upon the fortunate and make corpses of the rest.The gateway to the Expanse is littered with broken vessels and tales of the vanished.
The warp space of the Koronus Expanse is treacherous and unknown in the main, and partially explored regions of the Expanse are islands of Imperial activity admist a vastness of danger and mystery. Navigating is a far cry from traversing the established warp routes of the Calixis Sector.
Most of the Koronus Expanse is known to the Imperium only through legend, revelation, and hearsay. The Rogue Trader who ventures into this unknown risks his very soul upon the talent of his Navigator, and on quality of what little information he has gleaned from those gone before.
Beyond the partly explored regions of the Koronus Expanse, past deeps beset by pirates and dread xenos, lie many worlds and strange phenomena which exists as the stuff of dark legend.Some of these uncharted stars were visited by a single Rogue Trader whose tales are doubted and dismissed by rivals as outright lies, while others are known only from dubious and apocryphal sources such as Thulean data-vaults recovered from Dolorium's voids in 741.M41, or the infamous prophetic visions of the Seven Witches of Footfall.
Other fragments of contradictory lore relating to these dark zones are culled from even more untrustworthy sources, such as the muted Astropathic whispers overheard on the warp's twisted eddies, the falsehoods of the deceitful Eldar, or the ancient myths of heathen worlds given over to darkness for millennia uncounted.
Such areas are only labeled only as "Here be monsters" on ancient charts, where only the foolhardy of insane would venture to seek their destiny.
- The Koronus Expanse is the primary setting for the Rogue Trader role-playing game.
Stylized Map of the Koronus Expanse
- 1: Rogue Trader Rulebook, pgs. 335–362
- 2: Rogue Trader: Epoch Koronus
- 3: Rogue Trader: Citadel of Skulls pg. 7
- 4: Rogue Trader: Battlefleet Koronus, pg. 90
- 5: Rogue Trader Stylized Map (saved archive page, dated January 2020)