Segmentum: Ultima Segmentum
Sector: Umbral Sector
Classification: Fortress World
Subsector Capital: Illyrian Protectorate
Known for: Aurumite mining, warp anomalies, resistance to Chaos corruption, birthplace of the Illyrian Guard
Population: ~4.1 billion (concentrated in fortified bastions)
Notable Settlements: Bastion Aurex, Hive Orison, Cindral’s Gate, Auric Vale
Affiliations: Astra Militarum (Illyrian Guard), Astra Telepathica, Inquisition, Adeptus Custodes
(observer presence)
History
Age of Conquest (Great Crusade – M31)
Initially designated Sixty-Three Nineteen, Illyria was discovered by the Luna Wolves during the closing decades of the Great Crusade. When the Warmaster Horus Lupercal sent an emissary to negotiate peaceful compliance, the planet’s rulers responded with defiance and murder. Enraged, Horus personally led the assault, unleashing the might of the XVI Legion to subjugate the planet in a swift and savage campaign.
Following victory, Horus entrusted Praetor Teurtullian of the 13th Great Company with securing the wider Umbral Sector. Teurtullian initiated a systematic purge of separatist enclaves and implemented far-reaching compliance measures. Under his direction, Illyria was transformed into a bulwark world, its alpine bastions and subterranean strongholds forming the template for its future martial legacy.
Age of Darkness and the Scouring (M31–M32)
In the wake of the Horus Heresy, Illyria became a sanctuary for renegade Sons of Horus, including Teurtullian himself. Pursued by loyalist retribution, Teurtullian and his surviving fleet activated a mysterious xenos artifact buried in the Umbral Sector. The resulting catastrophe tore open a massive warp storm, shattering the C’tan Prison beyond the Gates of Varl and severing Illyria from the wider Imperium.
Teurtullian vanished soon after, presumed dead. He would emerge millennia later as Ygthemor the Deceiver, leading a Black Legion force known as the Magistri Noctis that would prove vital in Abaddon’s Black Crusades and mastermind the Fall of Cadia.
Age of Isolation and Rebirth (M32–M38)
For millennia, Illyria lay beyond Imperial reach, shrouded in an unyielding warp storm. Isolated and surrounded by Immaterium-bled landscapes, human survivors adapted. Successive generations developed latent resistance to warp corruption, shaping the population into a uniquely resilient stock—particularly attuned to psychic trauma without succumbing to it.
In M38, the veil lifted. The Rogue Trader dynasty of Von Valencius, led by Emiliana von Valencius, rediscovered Illyria and brokered its reintegration into the Imperium. Aurumite veins and the warp-hardened populace quickly drew the attention of the Inquisition, Scholastica Psykana, and Astra Militarum.
The Defense of Illyria (M40.999)
With the birth of the Great Rift, the Umbral Sector was plunged into disarray. Warp storms ruptured astropathic links, and daemons surged across sector boundaries. Amidst this upheaval, Illyria itself was invaded.
The Volscani Cataphracts—notorious traitors of the Fall of Cadia who hailed from the nearby world of Volscanor —led the attack, bolstered by renegade psykers, traitorous PDF regiments, and daemonic legions. Their aim was to desecrate Illyria and transform it into a warped shrine to Chaos Undivided.
Fierce resistance erupted across key settlements:
- Cindral’s Gate: A fortified mountain hive bastion whose defenses held back siege walkers and daemon engines for nearly a year
- Hive Orison: Site of street-to-street combat as Illyrian tanks and stormtroopers cleansed Chaos cultists block by block
- Auric Vale: Crystalline fields turned battlefield, where auramite detonations ruptured warp rift nexuses and purged daemons in fire and light
Under Inquisitorial directive, Protocol Obsidian was activated—initiating the evacuation of psykana assets, destruction of warp relics, and activation of long-dormant auramite-core defense grids. These ancient devices, relics of the Age of Strife, unleashed blinding psychic null fields and planet-wide disruption pulses that stunned the daemonic forces.
For three years Illyria fought alone without relief. Hellstalker Commandos waged brutal guerrilla campaigns behind enemy lines, conducting assassinations, demolitions, and sabotage of warp summoning sites. Civilian sacrifices and battlefield losses mounted.
The stalemate finally broke with the arrival of a Grey Knights strike cruiser and an Ark Mechanicus, whose orbital cleansing fire broke the siege and banished the worst of the daemonic hosts.
The aftermath was devastating. Over a billion lay dead and one-third of Illyria permanently warped into uninhabitable cordons. This event, known as The Great Sacrifice, forged the Illyrians into a people scarred yet unbowed.
From the smoldering ruins, the Illyrian Imperial Guard were formally inducted into the Astra Militarum.
Geography & Key Regions
- Cindral’s Gate: Mountain hive-bastion scarred by sieges and Chaos titan incursions
- Hive Orison: Subsurface and vertical city renowned for its layered defense strata and surviving Shrines of the Sainted Veil
- Auric Vale: Once-sacred auramite crystal fields; now riddled with warp scars and ruins consecrated by Grey Knights
- Cordons: Volatile wilderness zones touched by the warp—harboring strange temporal anomalies and daemonic bleed-through
- The Black Citadel: Headquarters of the Inquisition’s Umbral operations, and site of Hellstalker indoctrination
Strategic Significance
- Aurumite Mines: Warp-reactive material essential for Adeptus Custodes and Inquisitorial relic-crafting
- Population Genetics: Illyrians exhibit unique warp resistance—prime recruits for Astropaths, Navigators, and the Ordo Malleus
- Military Stature: Homeworld of the Illyrian Guard (aka Daemonslayers), famed for rapid mechanized warfare and anti-Chaos specialization
The Midnight Judges 