Sub-sector Aurelia is a sub-sector of the Korianis Sector which lies on the frontier of Imperial space. The inhabited worlds within this sector serve as the primary recruiting ground for the Blood Ravens Space Marine Chapter. In the late 41st Millennium, the entire sub-sector found itself consumed by war as first a splinter fleet of the Tyranid Hive Fleet Leviathan assaulted its inhabited worlds and then the Forces of Chaos sought to lay claim to the sub-sector and transform its former capital planet of Aurelia into a new Daemon World dedicated to the Ruinous Powers. These threats were countered by the Blood Ravens in the First and Second Aurelian Crusades. Finally, during the campaign known as the Cleansing of Aurelia or the Third Aurelian Crusade, the Blood Ravens were forced to confront the Chaotic corruption that had consumed the leadership of their own Chapter in the person of their Chapter Master and Chief Librarian Azariah Kyras even as the Ordo Hereticus of the Inquisition, led by the Radical Inquisitor Adrastia and the Imperial Guard forces seconded to her command, sought to unleash an Exterminatus upon the entire sub-sector to end the growing threat it posed to the rest of the Imperium.
Some key inhabited worlds within the Aurelian Sub-sector include:
- Meridian - Industrial Hive World that serves as the planetary capital of the sub-sector
- Aurelia - Ice World, recently restored to realspace after over 1,000 Terran years in the Warp
- Typhon Primaris - Dead World, formerly a Feral World infested by Feral Orks and Tyranids that was destroyed by an Exterminatus carried out on the order of Inquisitor Adrastia
- Cyrene - Dead World, formerly a Civilised World that fell to Chaotic corruption and was destroyed by a Blood Ravens Exterminatus ordered by Gabriel Angelos, the current Chapter Master of the Blood Ravens
- Calderis - Feudal World/Desert World - Calderis is known for its arid climate and the hardy desert warriors its difficult environment produces. The Blood Ravens have recruited from this world for millennia. An Imperial Planetary Governor oversees the planet from a space station in orbit.