Sterilization of Geonosis Some time between 14 BBY and 3 BBY , the Outer Rim world of Geonosis was sterilized by the Galactic Empire , killing most of the planet ' s population , by orders from Grand Moff Wilhuff Tarkin , to ensure the secrecy of the Death Star project . The Geonosian s of the Stalgasin hive were the original builders of the Death Star , an armor ed battle station capable of destroying entire planets . During the Clone Wars , they were persuaded to aid in the battle stations construction by Lieutenant Commander Orson Callan Krennic . At the end of the war , Supreme Chancellor Palpatine declared himself Emperor and transformed the Galactic Republic into the Galactic Empire . The Death Star project fell under Imperial control and the battle station was moved away from Geonosis . The only survivor of the sterilization was Klik - Klak , who at some point after came into the possession of a Geonosian egg who when hatched became Queen Karina the Great , she eventually moved to a lair beneath the planet ' s surface . Unable to produce new offspring and thus unable to repopulate the species , Karina continued the production of battle droid s that the Geonosian droid factories once produced . The Sith Lord Darth Vader came to Geonosis during the Galactic Civil War and took the droids from her . Prelude . Prior to the outbreak of the Clone Wars , the Geonosian s designed an Ultimate Weapon for the Confederacy of Independent Systems . This weapon , later known as the Death Star , was an armor ed battle station capable of destroying entire planet s . When the Clone Wars broke out on their homeworld of Geonosis , the designs for the Ultimate Weapon were taken by Count Dooku , a Sith Lord and leader of the Separatist Alliance , to his master , Darth Sidious , on Coruscant . Sidious was secretly Supreme Chancellor Palpatine , who led the Galactic Republic and controlled both sides of the war . His goal was to transform the Republic into a Galactic Empire and rule the galaxy as Emperor . The sterilization . Sidious ' goals came to pass at the end of the Clone Wars . The Separatists were defeated , and the Republic was transformed into the Empire . The Death Star continued its construction over Geonosis under the supervision of first Vice Admiral Dodd Rancit , and later Moff Wilhuff Tarkin , but it was eventually moved to another location . Ordered by Tarkin , now a Grand Moff , the Imperial Weapons division sterilized Geonosis using Imperial gas canister s , destroying all but one of the planet ' s population of approximately 100 billion , resulting in the largest genocide ever committed by the Empire . Aftermath . In the third year before the Battle of Yavin , the rebel crew of the starship " Ghost " traveled to Geonosis after receiving an intelligence report suggesting that the Empire was building something over Geonosis . When they arrived , they found only Imperial construction modules that had once supported the Death Star ' s construction , though the rebels were unaware of what was being constructed there . The intelligence was , in reality , a trap to lure the rebels to Geonosis . Agent Kallus of the Imperial Security Bureau led a group of stormtrooper s in ambush against the rebels on one of the modules , but the rebels were able to escape . One of the rebels , Garazeb Orrelios , was stranded on Bahryn , an icy moon of Geonosis , with Agent Kallus after an escape pod they were in crashed . Before they were rescued , Orrelios learned that Kallus was unaware of what happened on Geonosis . He did not believe that the Empire had any reason to exterminate an entire population , but Orrelios said he was simply in denial . The following year , Senator Bail Organa dispatched Saw Gerrera and his Partisans to investigate the apparent disappearance of the Geonosian species . Saw and his team were ambushed and attacked by Klik - Klak , who mistook them for hostiles . After Rebel Command lost contact with Saw and his team , Senator Organa dispatched the Spectres and the former Clone Captain Rex to continue Saw ' s mission . After reuniting with Saw , the Spectres and Rex captured Klik - Klak . A disagreement ensued between Saw , who wanted to take Klik - Klak offworld for interrogation , and the Spectres , who wanted him to remain on Geonosis . The rebels were forced to take their ship " Ghost " into the depths of Geonosis after they were attacked by a light cruiser commanded by Captain Brunson . Down there , the rebels discovered the poison canisters which the Empire had used to perpetrate genocide against the Geonosians . The rebels managed to flee Captain Brunson ' s cruiser but were unable to bring back physical evidence of the poison canisters . However , the rebellion was able to use visual images of the canisters to rally more worlds to the rebel cause . Several years later , during the Galactic Civil War , the Sith Lord Darth Vader and the archaeologist Doctor Aphra went on a secret mission to Geonosis in order to acquire battle droid s for use in his personal army . They found Karina the Great and discovered that she was continuing to manufacture battle droids , as the Geonosian droid factories once did before and during the Clone Wars . Vader took her battle droids , but left the queen alive . The rebel leader Mon Mothma ' s Declaration of Rebellion indirectly referenced the Geonosian genocide when it condemned the Galactic Empire for instituting a " blatant policy " of speciesism and genocide against the non - human populations of the galaxy . Behind the scenes . It was implied on " Rebels Recon " that the genocide was committed to keep the construction of the Death Star over Geonosis a secret .