The Aberrus System is an Imperial star system located in the Eastern Fringe of the Imperium Nihilus close to the Grendl Stars. It is currently gripped in a conflict between the military forces of the Imperium of Man and a tendril of the Tyranids' Hive Fleet Kraken known as the War for the Aberrus System.
The invasion of the system by the Tyranids in the Era Indomitus was picked up by the ancillary scry-station located on Hedhan, the outermost world of the system, that was controlled by the Iron Lords Chapter of Space Marines. The Chapter homeworld of the Iron Lords was Sternac, which was located close to the Aberrus System.
But if Hive Fleet Kraken managed to overrun the Imperial defenders of the Aberrus System, then they would be able to sweep into the Grendl Stars, potentially adding the Barghesi's savage genetic diversity to their own. The Ordo Xenos feared that were Aberuus to fall, the fate of the entire Eastern Fringe could be put at risk.
The following six worlds orbit the Aberrus star, listed in order from closest to farthest from the star.
- Vander's Folly (Dead World)
- Ligrides (Dead World)
- Luann (Jungle World) - Luann is one of the two Human-settled worlds of the Aberrus System, the other being Glacemaw. Luann is home to its own militarum regimento of the Astra Militarum, the Luann Lineholders, who were heavily engaged in the battles to save the world from the hundreds of millions of Tyranid bioforms who are currently seeking to claim it. Luann's ecosystems were home to extremely carnivorous fauna, which had been contained by a string of fortresses known as the Four Towers. These fortresses are now under siege by the Tyranids as is the Hinnoq Delta Tribridge, where the 81st and 935th Luann Lineholders Regiments assigned to its defence proved unable to withstand the pressure and collapsed.
- Glacemaw (Ice World) - Glacemaw is the second Human-settled colony world of system. It is a frigid planet, marked by sweeping tundras. It is also home to an Astra Militarum militarum regimento, in this case the Glacemaw Ridgeguards. Glacemaw, like Luann, has also been invaded by hundreds of millions of Hive Fleet Kraken bioforms and hundreds of the feared Tyranid Bio-Titans. The Permaberg Citadel has already been toppled by the Tyranid assault, The Tredi Forest on Glacemaw, viewed as impenetrable for millennia, was all but consumed -- only by the efforts of the Catachan Jungle Fighters LV Regiment, supported by the Knights of House Curtana and House Borgius and the Sisters of Battle of the Order of the Crimson Chalice, had the outer reaches been held. The Sanctuary of Saint Vilutia was sure to fall if the forest was lost. The ice fields of Kutris crawled with Tyranid bioforms rampaging towards the major settlement of Glation City, which was expected to be destroyed within three local days of a concerted attack by the Tyranids.
- Saint Vaux's Hope (Mining World) - Saint vaux's hope has already fallen to the Tyranids, its enitre biosphere consumed by the maw of the great Devourer.
- Hedhan (Iron Lords Ancillary Scry-Station) - This world long served as the base for a scry-station or observer's post of the Iron Lords Chapter. When this scry-station picked up the Tyranid invasion of the Aberrus System, it relayed its warnings to the Iron Lords who initiated the Adeptus Astartes reinforcements who have recently joined in the War for the Aberrus System, providing renewed hope and morale for the beleaguered defenders.
- Codex: Space Marines (9th Edition), pp. 24-25