Battle of Ilum The Battle of Ilum , also known as Operation Dark Ice , was a conflict in the early years of the Galactic War between the Galactic Republic and the Sith Empire . It initially began as a battle between the Empire and the Republic on the remote planet of Ilum for control of the planet ' s Adegan crystal s . However , Darth Malgus seized the initiative , declared himself Emperor , and called on his fellow Sith to join his " New Empire " . In response , both the Republic and the Sith Empire temporarily set aside the battle with one another to confront this new threat . Upon slaying Malgus ' lieutenant , Darth Serevin , the combined forces attacked Malgus ' mobile space station and destroyed his armies , before defeating Malgus himself in his throne room . Prelude . After the Sith Empire had discovered that the Adegan crystal on Ilum possessed innate stealth properties , Imperial officers - particularly Grand Moff Ilyan Regus , the successor to the late Rycus Kilran - dreamed of using the planet ' s resources to create a fleet of stealth warships for the Imperial Armada . In 3641 BBY , Regus and Dark Council member Darth Arho led Imperial forces in an invasion of Ilum codenamed " Operation Dark Ice " . In response , the Republic sent a considerable army to stop them , under the leadership of Supreme Commander Rans and Jedi Master Jaric Kaedan . The battle . The Empire made tremendous gains in the initial phases of the battle , slaying Master Kaedan and Admiral Shai . Forces under the personal command of Darth Arho were also able to capture Supreme Commander Rans during a sneak attack on the Republic base camp in the eastern ice fields . As the Republic commanders fretted on what to do next , they were contacted by an unlikely ally : Darth Malgus , a man known for his desire to destroy the Republic , but willing to accept the reality that the Republic was the victor , and it required Sith of a more " progressive " mindset in order to save the Empire . During the battle , the Republic ' s Talz commandos carried out an operation codenamed " Shatterstorm . " Transmissions mentioning the operation were intercepted by the Operative Che ' nash of the Shrikaansi Reconnaissance Company , who was unable to proceed on her own and hired in Imperial to infiltrate the Talz camp and extract more information from their communications grid . Malgus revealed that he had secretly been in contact with Rans , feeding him information on how best to deal with Darth Arho , who Malgus considered a " thug " despite being on the Dark Council . He informed the commanders , and the Republic and Jedi heroes answering the call to arms on Ilum , that Rans was being held at a prison camp to the west of their base , guarded by sensitive sensor towers that would trigger alarms if anyone attempted to enter the base . Malgus provided the codes to deactivate the sensor towers , allowing the Republic forces to free Rans and some of his soldiers . With Malgus ' aid , the Republic forces tracked down Arho himself to the ruined Jedi Temple . Though Arho was incredibly powerful with the Force , he was no match for his opponents . A new Empire . Despite Arho ' s death , the Empire had gathered a vast resource of Adegan crystals , achieving the goal of their operation . However , Malgus seized the fleet carrying the crystals , much to the consternation of Grand Moff Regus . Shortly afterwards , Malgus transmitted a message across the entire galactic HoloNet . In it , he condemned the apparent apathy ( and later disappearance ) of the Sith Emperor , and the infighting and xenophobic mentality of the Dark Council and the Sith as a whole . Thus , he declared a " new Empire " , open to all warriors willing to follow him , and decreed that the Dark Council be dissolved . Malgus ' declaration blindsided both the Republic and the Empire , both of whom summoned emergency councils of war to respond to the threat . With such a wealth of Adegan crystals at his disposal , Malgus could create a stealth armada that would make him virtually invincible , and perfectly capable of carrying out his designs for a new war of conquest . Making the first move , Malgus dispatched Serevin to lead an invasion of Ilum to destroy the Republic and Imperial forces there . Both sides believed that capturing a stealth fighter with the command codes would allow them to locate Malgus himself . Cole Cantarus of the Corellian Security Force and General Hesker of the Imperial Guard , both veterans of the battle for Corellia , flew their respective strike teams to the front lines to confront Serevin and his forces at Fort Barrow . Serevin faced his attackers accompanied by Voss Mystics and Commandos he had recruited during his period as a diplomat in Voss - Ka . Serevin was struck down , and the combined forces took control of his stealth fighter . The ship ' s computer provided coordinates to the Emperor ' s Fortress , commandeered by Malgus after the Voice of the Emperor was defeated by the Hero of Tython . Rather than waste time translating the coordinates and taking their own ships , the combined forces took the stealth ship and landed onboard Malgus ' space station . The army at Malgus ' command on the space station included a wide variety of troops : defecting Sith and Imperial soldiers , Trandoshan warriors , Mandalorian mercenaries , Anomid scientists , and extermination droid s from the Foundry , a Rakata space station captured by an Imperial strike team at Malgus ' direction . The Anomids , belonging to a group known as the Schism Collective , had been behind the successful creation of Malgus ' stealth armada , and also outfitted the station and the troops with salvaged Rakata technology from the Foundry . Fighting their way through the station ' s halls , they found Malgus in his throne room . As the enemy forces outside began to press the attack , Malgus activated the station ' s self - destruct sequence , which would incinerate the station and the attacking fleets , before leaping down from his throne to face his attackers . Decades of fighting on the front lines made Malgus a formidable opponent , but his attackers managed to gain the upper hand . Seizing an opening as Malgus ' resolve faltered , the attackers used Force powers and pulse grenades to force him off the central platform of the station . The self - proclaimed Emperor fell from the platform and down the reactor shaft , presumably to his death . His " new Empire " would die while he disappeared . Aftermath . After Malgus ' defeat , Ilum was firmly in the hands of the Republic , and the Empire had managed to reclaim the Adegan crystals it had taken from the planet . But Malgus ' rebellion was a major blow to the Imperial war effort ; combined with the infighting amongst the Sith and the reversals of fortune on the battlefield , the Empire was brought to the brink of collapse by the following year , leaving its surviving leaders to hope for a miracle that would prevent their downfall . Two year after the Battle of Ilum , a seemingly insignificant world located on the border between the Republic and Hutt Space came to their attention as a possible solution to the Empire ' s misfortune : Makeb .