Tarnis ( Sith Lord ) Tarnis was a Human male Sith Lord of the resurgent Empire who lived during the Great Galactic War and the subsequent Cold War with the Republic . The son of the legendary Darth Angral , Tarnis was trained by his father ' s apprentice Lord Praven to the rank of Sith Lord before embarking on an undercover assignment not long after the Treaty of Coruscant ended the Great Galactic War . Posing as the Republic scientist Eli Tarnis , he infiltrated the Republic ' s superweapon projects and quickly became the head of the design team for the Planet Prison weapon on the Republic ' s capital Coruscant . While his initial purpose was to gather information from inside the Republic , Tarnis believed his cover was in danger in 3643 BBY when the Jedi Master Bela Kiwiiks arrived on Coruscant to investigate a " dark presence " the Jedi Council had sensed on the capital . He made his move and attempted to steal the Planet Prison with the help of the criminal organizations known as the Migrant Merchants ' Guild and Black Sun . Staging his own kidnapping from the Senate Building after hiring a thief to steal the design files for the Planet Prison , Tarnis fled to the territory of the paramilitary Justicars ' Brigade , but was pursued by a young Jedi Knight . Tarnis ' true identity was uncovered by the Jedi Knight , working with the Republic Strategic Information Service , the Coruscant Security Force , and the Padawan Kira Carsen , and the Sith was followed to the ruins of the Jedi Temple , where the Knight and Carsen faced the Sith Lord in a duel in order to stop him from using the Planet Prison against Coruscant itself . Tarnis ' death was witnessed via hologram by his father , who declared everlasting vengeance upon his son ' s killer and embarked on a crusade to gain revenge upon the Jedi . Biography . Early life . A Human male , Tarnis was born the son of the Sith Lord Darth Angral sometime during or before the Great Galactic War with the Galactic Republic . Found to have inherited his father ' s Force - sensitivity , he was trained by the pureblooded Sith Praven — one of his father ' s own Sith apprentices . Tarnis ascended to the rank of Sith Lord sometime before the Sacking of Coruscant in 3653 BBY , when his father led an invasion fleet to capture the Republic capital and Tarnis ' teacher joined Darth Malgus and Lord Adraas in destroying the Jedi Temple . When Darth Baras negotiated the Treaty of Coruscant and ended the Great Galactic War , Angral was furious to be denied the chance to crush the Republic once and for all . Tarnis inherited his father ' s hatred of the Republic as well , and was sent undercover on Coruscant by Angral as a scientist not long after the treaty . The man put his scientific genius to use as part of the Mon Calamari General Var Suthra ' s superweapon projects , where Tarnis and other scientists worked to weaponize technologies developed by the brilliant Doctor Nasan Godera during the war . As Doctor " Eli Tarnis , " it was not long before the Sith became the chief scientist for the entire division during the tense Cold War , and while he did contribute significantly to the other designs such as the Shock Drum and the Death Mark laser , he worked primarily on the Planet Prison — a weapon designed to ionize a planet ' s entire atmosphere , preventing any starships from leaving or entering the atmosphere and effectively blockading a planet without any additional naval firepower . However , Tarnis also developed a way to combine the different weapons into something he called the Desolator , though he kept his research a secret . Deception . By 3643 BBY , the Planet Prison was reaching the prototype stage , and the scientists were preparing to start trials when the Jedi Master Bela Kiwiiks arrived on Coruscant to investigate a darkness that the Jedi Council sensed on the capital . Fearing that his cover would soon be exposed , Tarnis set in motion a plan to seize control of the Planet Prison and escape from Republic territory . Contacting the criminal syndicate known as Black Sun , Tarnis revealed his true identity as a Sith Lord and made an offer to Salarr , Black Sun ' s leader . In exchange for advanced weapons and armor from the Sith Empire , acquired through Tarnis ' allies in the Imperial - friendly Justicars ' Brigade paramilitary group , Black Sun would aid Tarnis in the elaborate deception he was about to perpetrate . At Tarnis ' request , Black Sun enlisted the Rodian thief Vistis Garn — who often worked for Black Sun ' s rival , the Migrant Merchants ' Guild — to steal the design files for the Republic superweapons . A team of Guild members under Garn ' s leadership raided a military warehouse and stole a shipment of heavy weapons in addition to the design files Tarnis had requested . Just over thirty hours later , Tarnis was summoned to the Senate Building for a meeting with General Suthra and the Jedi Masters Orgus Din and Bela Kiwiiks , as well as Kiwiiks ' apprentice Kira Carsen . Kiwiiks was concerned that Tarnis seemed not to care about the missing files , and the Doctor was irritated that the Jedi were against the development of the Planet Prison — it was a humane defensive weapon . Not long into the conversation , Din ' s former student arrived , and General Suthra departed the conference room with the two Jedi Masters for a meeting with Supreme Chancellor Dorian Janarus when the Mon Calamari ' s subordinate Agent Galen arrived with news : A member of the Republic Strategic Information Service , Galen and his team had identified Garn as one of the thieves and tracked him to the Old Galactic Market , a region under the control of the Merchants ' Guild . While Carsen worked with Galen to distract the criminals with the Coruscant Security Force ' s security network , Din ' s apprentice — a recently elevated Jedi Knight — traveled to the Old Galactic Market with the astromech droid T7 - O1 in order to recover the weapons and plans . While the duo raided the warehouse where Garn was holed up , Tarnis contacted Black Sun and set the second stage of his plan in motion . Taking advantage of the preoccupation of Suthra and Galen ' s forces , Tarnis gave a Black Sun team inside information on the Senate Building ' s defenses so that they could sneak inside and " kidnap " him . The plan worked perfectly , and Tarnis disappeared from the building before security realized the criminals were there . The Black Sun criminals retreated to the Coruscant Spaceport in order to serve as a distraction , while Tarnis himself took an air taxi — but instead of going to the gang ' s territory as planned , he traveled to the territory of the Justicars so that he could prepare for the third stage of his plans . While the Black Sun lieutenant Zeer and his men fought the Coruscant Security Force in Docking Bay 84 to protect their " prize , " Tarnis transmitted a secure message to the five other members of the Planet Prison design team . He informed his subordinates that the Jedi had discovered the project and were planning to shut it down , convincing them that the only way to save the project was to bring him the prototype deep in the Justicars ' Sector . Believing their superior , the five stole the prototype from their lab and journeyed deep into the region to meet with Tarnis at the Justicars ' Tower . During that time , the Knight had joined forces with Carsen to break through the kidnappers ' lines and learned from Zeer that Tarnis had been taken to Black Sun Territory . General Suthra was alarmed to discover that the files stolen by Garn had contained information on all of the Republic ' s weapons projects , and so Masters Din and Kiwiiks departed Coruscant along with Agent Galen to secure each offworld facility . Galen had first put the Knight in contact with the CSF ' s Special Tactical Unit , and the Jedi had traveled deep into Black Sun Territory with T7 - O1 to meet up with the police officers . The Knight and Sergeant Nidaljo ' s men staged their attack on Salarr ' s headquarters and quickly broke through the criminals ' defenses , causing the Black Sun leader to contact Tarnis in a fury . Tarnis brushed off Salarr ' s accusations of treachery and ordered the criminal to kill the Knight , who had just entered the room and discovered the " Doctor " talking to Salarr via holocomm . When the Jedi accused him of treason , Tarnis revealed his true identity as a Sith Lord before terminating the conversation so that he could meet with his design team . Betrayal . The five scientists gratefully handed control of the prototype over to Tarnis , but were horrified when their superior turned on them and drew his lightsaber , unleashing lightning from his fingertips as he cut them down . The Sith Lord made quick work of the defenseless scientists , though one man — Jonkan — was only wounded mortally and witnessed the Sith depart with the prototype . Tarnis descended into the industrial sector known as the Works , where he was escorted to the ruins of the Jedi Temple by Imperial soldiers and began to set up the Planet Prison in the chambers of the Jedi Council . Jonkan managed to hold on long enough for the Jedi Knight to arrive with Carsen , and in his last moments explained that the device needed time to charge — and that it generated immense amounts of heat . Using the scientist ' s information , the two Jedi were able to locate the weapon in the Jedi Temple and raced to the ruins , cutting through the Imperials who attempted to stop them . As he waited for the device to charge , Tarnis contacted his father via a secure holotransmission threaded through Ord Mantell and several other planets , and informed both Angral and his father ' s three apprentices — Sadic , Praven , and Nefarid — of his success . Angral was greatly pleased by his son ' s accomplishments , and was in the process of praising Tarnis when the Knight and Carsen stormed into the room . Sadic mocked Tarnis for leaving loose ends , but Angral urged his son not to allow the Jedi to stop their victory . Refusing the Knight ' s offer of surrender , Tarnis summoned his red - bladed lightsaber to his hand and unleashed a storm of violet lightning at the two Jedi before charging . Though Tarnis was skilled with his blade and in the use of the dark side of the Force , he was ultimately no match for the younger Jedi ' s martial skill and strength in the Force , and their duel ended when the Knight struck down the Sith Lord before the unbelieving eyes of Tarnis ' father . Legacy . Tarnis ' death drove his father to the brink of insanity , and Angral declared war upon the Republic in his effort to exact revenge upon the Jedi Knight who killed his son . Seizing control of the Republic ' s superweapon projects , Angral used his son ' s research on combining superweapon technologies — Tarnis ' final gift to his father — to combine the stolen weapons into the planet - killing Desolator . After successfully testing the weapon on the agriworld Uphrades , Angral attempted to destroy the Jedi Order ' s homeworld of Tython , but the Knight was able to defeat the elder Sith Lord aboared his flagship " Oppressor " , ending the threat of the Desolator forever . When Praven faced the Knight on the desert world of Tatooine , he understood that the Jedi ' s power was what ultimately led to his student ' s death , and the Sith was satisfied to know that his training had not been at fault . Tarnis ' work on the Planet Prison would later be adapted into the weapons known as the Firestorm Turbolaser s by Imperial scientists during the Battle of Corellia several years later . Personality and traits . A Human male with green eyes like his father ' s , Tarnis had brown hair and pale skin in his mild - mannered " Eli Tarnis " persona . However , when Tarnis dropped the facade , the power of the dark side visibly darkened and grayed his skin , and he wore a dark hooded cloak . Tarnis was an arrogant and cruel man , and some of it bled through his disguise in that he was considered stuffy and self - important as a scientist . As a Sith Lord and the son of Darth Angral , he believed himself invincible and trusted fully in the power of the dark side to destroy his enemies and ensure his victory . Once he no longer had need of allies like Salarr , Black Sun , and even his research team , he cast them aside and continued his own plans with complete confidence that he would succeed . His arrogance stemmed from both his brilliance and his strength in the dark side , and Tarnis was willing to use both to achieve his objectives . Powers and abilities . As the son of the powerful Sith Lord Darth Angral , Tarnis inherited his father ' s strength in the Force and was trained by Praven as a Sith . In battle , Tarnis wielded a single red - bladed lightsaber with considerable skill , but relied more upon his use of Force blasts and lightning . The Sith ' s true skills lay in subterfuge , as Tarnis was skilled enough to maintain his cover for almost a decade , and in science — the man was a genius . Tarnis ' work brought significant advancements to the superweapon projects , and he also developed a way to combine the Shock Drum , Death Mark , and Planet Prison weapons into a single ship - mounted weapon — a feat that even the renowned Doctor Nasan Godera , the creator of those weapon technologies , acknowledged as pure brilliance . Behind the scenes . Tarnis first appeared in " " , a released by BioWare and LucasArts on December 20 , 2011 . The ultimate antagonist of the Coruscant section of the Prologue for Jedi Knight class , he is first encountered as " Doctor Eli Tarnis " in the mission " The Jedi Envoy " . Tarnis is the target of the missions " Kidnapped ! " , " Rescue " , " Tracking Down the Traitor " , and " Race to the Ruins " , though his identity as a Sith Lord is not revealed until the end of " Rescue " . When the player faces Tarnis in the Jedi Temple , they can choose to ask him to surrender for light side points , or attack for dark side points , but regardless of the player ' s choice they will fight and kill Tarnis . Tarnis is also mentioned in the 2012 reference guide " " , in the entries on Darth Angral and the Jedi Knight class storyline . In the 2015 Digital Expansion " " , Tarnis appears as an enemy for Jedi Knight players during the hallucination scenes in Chapter 2 .