Mission to Justicar territory In 3643 BBY , during the Cold War between the Galactic Republic and the Sith Empire , a young Jedi Knight and the Padawan Kira Carsen embarked on a mission to the heart of Justicar territory , home of the paramilitary Justicars ' Brigade on the Republic capital planet of Coruscant . The Jedi ' s goal was to retrieve the Planet Prison , a Republic superweapon that had been stolen by the scientists on the project at the behest of their leader , Doctor Tarnis . However , the scientists were unaware that Tarnis was , in fact , a Sith Lord . The Sith had killed the research team and stolen the Planet Prison by the time the Knight and Carsen reached the Justicars ' Tower , where they had traced an earlier transmission by Tarnis . The only surviving member of the team , a fatally wounded man named Jonkan , helped the two Jedi locate the Planet Prison in the depths of the Jedi Temple . The Jedi subsequently pursued Tarnis and defeated him in a duel before deactivating the weapon and thwarting the Sith ' s plan to use it against the Republic capital . Prelude . In 3643 BBY , during the Cold War between the Galactic Republic and the Sith Empire , the Republic and the Jedi Order became aware that Doctor Eli Tarnis , the lead scientist on the Republic ' s Planet Prison superweapon project , was , in fact , a Sith Lord . Tarnis ' s cover was exposed when he arranged for the theft of files on the Republic superweapon initiative and allied himself with the Black Sun criminal syndicate . Tarnis contacted his research team , the members of whom were unaware of his true identity , and urged them to bring him the Planet Prison prototype , as he claimed that the Jedi were planning to shut down the project . Believing Tarnis , the five scientists secured the prototype and took it to Tarnis deep in Justicar territory , the territory of the paramilitary and Imperial - friendly Justicars ' Brigade . A young Jedi Knight and the astromech droid T7 - O1 had launched a rescue mission in the territory of Black Sun after Tarnis had arranged for Black Sun to stage his kidnapping from the Senate Building , but instead of finding the scientist , the Jedi Knight learned of Tarnis ' s duplicity and his true identity as a Sith . Returning to the Senate Building , the Knight was sent by General Var Suthra of the Republic Military to pursue Tarnis and the stolen Planet Prison to the Justicars ' Sector , where the origin of Tarnis ' s transmission to the Knight had been traced . The Jedi Padawan Kira Carsen accompanied the Knight in case the pair encountered the Sith Lord in their search , and the two set off for the Justicars ' Sector . The mission . As the two Jedi took an air taxi to the Justicars ' Sector , Tarnis met with his research team in the Justicars ' Tower , the Brigade ' s prison and interrogation center . Once he had obtained possession of the Planet Prison , Tarnis turned on them , revealing himself to be a Sith and then murdering them with Force lightning . However , one of the scientists , a man named Jonkan , was only gravely injured , and he watched as Tarnis departed with the Planet Prison prototype . The Knight and Carsen were forced to fight their way through hostile Justicars to reach their destination , but by the time they arrived , Tarnis had already left the area , and the two Jedi found only the bodies of the research team and a dying Jonkan . Knowing he was severely wounded , Jonkan shrugged off the Jedi ' s reassurances that they would get help and quickly explained what had happened . In his final moments , Jonkan explained how the Knight and Carsen could track the Planet Prison : The device generated enormous amounts of heat and required time to charge to full capacity , giving them time to find and destroy the weapon before it could fire . Urging the Knight to save Coruscant , Jonkan gasped his final breath and passed away . Aftermath . Using Jonkan ' s information , Carsen tracked the location of the Planet Prison using the room ' s computers . Tarnis had taken the weapon to the ruins of the Jedi Temple as a final insult to the Jedi . With no time to spare , the two Jedi raced through the Works , Coruscant ' s industrial and infrastructure district , toward the Temple and their final confrontation with Tarnis . The pair located Tarnis in the ruins of the Temple and defeated him in a duel , though Tarnis ' s death incurred the wrath of his father , Darth Angral . Behind the scenes . The mission to the Justicar ' s Sector was created for " " , a massively multiplayer online role - playing game released by BioWare on December 20 , 2011 . It appears in the Jedi Knight - class story mission " Tracking Down the Traitor , " in which the player pursues the Sith Lord Tarnis to the Justicars ' Sector in an attempt to find the Planet Prison superweapon . While the mission does not feature any alignment choices , it is notable for being the first mission in which the player receives Kira Carsen as a companion . She serves as a guest companion for this and the next mission , which means that she cannot be sent on crew skill missions .