Vul Isen Vul Isen was a Force - sensitive Givin male who served the One Sith as a scientist . Born into the One Sith on Korriban , his talents did not lie in combat , but in science , so he was never given the coveted " " Darth " " title . Isen worked extensively with bioweapon s , and was experienced in committing genocide and ruining planets with such toxins . He found no sorrow or regret in these actions , thinking of it as a sort of game . In 137 ABY , after Darth Krayt ordered the genocide of the Mon Calamari species , Isen was posted to the planet Dac , to work alongside overseer Darth Azard in speeding up the extermination of the Mon Calamari . Tension ran high between Isen and Azard , who felt that the Givin was a lesser Sith for not having a " Darth " name and disliked his inquisitive nature . Because Krayt wanted only the Mon Calamari and not any of the world ' s other inhabitants targeted , Isen was unable to use his experimental viral organisms which would reduce the planet to a desolate swamp world . Instead , he turned to ancient Sith lore and alchemically engineered a Sea Leviathan , the first of its kind adapted for underwater use . Isen and Azard hoped the beast would help them eliminate the remaining pockets of Mon Calamari as quickly as possible . The Leviathan led Isen and Azard to the base of the Mon Calamari Rangers , but the Sith ' s Aquatic Terrain Armored Transport was rammed by one of the Mon Calamari , crippling the vessel . Isen survived uninjured , but Azard was trapped under shrapnel . Using Azard ' s lightsaber , the Givin scientist freed him , to Azard ' s surprise , and the two swam toward the surface . The Leviathan was meanwhile defeated by Imperial Knight Treis Sinde and hordes of devilsquid . A short time later , Isen was ordered to execute the Final Protocol , the elimination of the entire life on the planet , a task Isen was more than willing to complete . His actions caused the deaths of more than eighty percent of Dac ' s population , earning him the nickname of the " Butcher of Dac " . Isen was eventually killed by Cade Skywalker after attempting to pollute the population of Utapau . Biography . Scientist . Vul Isen was a Force - sensitive Givin male , who lived over a hundred years after the Battle of Yavin . He was born on the One Sith stronghold planet of Korriban , and was inducted into the One Sith , along with many other Sith born on the world . However , Isen ' s field of expertise was not combat , but rather science . Thus , he was not given the " Darth " title awarded to the most skilled of the One Sith ' s warriors , for which he was looked down upon by those who felt such Sith were of lesser importance than the warriors . After leaving Korriban , Isen did not carry a lightsaber or wear the dark robes worn by many of the Sith warriors , instead donning a uniform similar to that worn by the Sith ' s military officers . Isen became very knowledgeable and skillful in his chosen field , and he became an expert on exterminating or pacifying species who resisted the Sith ' s rule . Isen engineered various destructive organisms that could eradicate masses of life and reduce planets to swamps , though , according to him , he did not get a chance to properly try out many of these . Unlike the sort of warriors who looked down on him , Isen was not unflinchingly obedient towards the One Sith ' s leader , Darth Krayt , and he had no qualms about questioning orders that did not make sense to him ; he felt that as a scientist it was his duty to question everything . In 137 ABY , Krayt initiated the Genocide of Mon Calamari , ordering all members of the Mon Calamari species on the planet Dac to be either killed or put into slave labor camps , as punishment for working against Krayt ' s Empire . Following the Massacre of New Coral City , many Mon Calamari fled to the depths of the planet ' s oceans , though , and Isen was tasked with using his knowledge to help eliminate them more quickly . Darth Azard , a Quarren Sith Lord , was posted to Dac to oversee the extermination , and Isen worked directly under him . The Sea Leviathan . Because Krayt wanted only the Mon Calamari eliminated and not the Quarren or any of Dac ' s other native species , Isen would not be able to release experimental viral organisms to wipe out all life on the world , so the Givin consulted several other , high - ranking Sith about how best he could speed along the process while ensuring only the Mon Calamari were targeted . Darth Maladi , Krayt ' s foremost scientist and torturer , was thoroughly unhelpful , refusing to share her knowledge with him . Darth Wyyrlok , Krayt ' s most trusted advisor , suggested Isen look to older Sith lore , and to explore the possibility of adapting a Leviathan — alchemically bioengineered Sithspawn created by Dark Jedi that predated the Sith — for use in the sea . The creature , when completed , would be able to eliminate the remaining Mon Calamari on Dac . Though semi - sentient , the Leviathan would absorb the life energies of those it killed , becoming sentient and driving it to think like a Mon Calamari , enabling it to better locate their hiding places . Isen spent weeks engineering the creature in the gaping , underwater Soheras Trench , reaching the trench via an Imperial Aquatic Terrain Armored Transport , until the first Sea Leviathan was ready — all it needed was a spark of the Force to awaken it . Isen and Darth Azard traveled together to the trench in a transport . Azard was one of those who felt that members of the One Sith who had not earned the " Darth " title were lesser than he , and he disliked Isen ' s lack of complete obedience to Krayt ' s rule . As the transport traveled , Isen attempted to make conversation , telling the other that he would rather just kill off the entire world . When the Sith reached the edge of the abyss , Isen and Azard used the Force together to awaken the creature , imprinting their minds and wills upon the creature and providing it with its orders . The first Sea Leviathan rose from its place of slumber and went straight for a nearby enclosure of enslaved Mon Calamari , sucking up the captives ' life energies . Isen explained the process of absorbing the life forces , though Azard had doubts about it , fearing that the Leviathan may start to think like a Mon Calamari too much , and attack the Imperials . Isen was confident that this would not happen , and managed to dissuade Azard . Rooting out the resistance . Darth Azard already had a target in mind to set the Sea Leviathan on . Earlier that day , an Imperial Acklay Battle Fortress , the " Sea Lion " , had been attacked and disabled by a group of Mon Calamari Rangers , part of the resistance against the Empire on Dac , while tracking a group of refugees . Azard ordered Isen to send the beast towards the refugees ' location , so as to draw out the Rangers and defeat them in one swift blow . Isen was impressed with Azard ' s plan , and began to execute it immediately . The Leviathan , followed by Isen and Azard in their transport , soon came upon two Mon Calamari Rangers piloting underwater Krakana fighters . The Mon Calamari tried to evade the creature , but Isen ' s shuttle was able to damage one who had escaped the Leviathan ' s reach . The creature subsequently absorbed the life energies of the damaged ship ' s occupant , but one Krakana managed to escape , and its pilot sped back to her comrades in the Rangers ' base . Isen ordered his gunners to allow the Mon Calamari to escape unhindered , so that she could inform the Rangers that the Imperials were coming for them ; a Mon Calamari defeat , Isen felt , was inevitable , but he felt it would be easier to finish off the Mon Calamari if they swarmed into the same locations , rather than having to hunt them down individually . Isen informed Azard that he preferred breaking the will of a species , sparking a minor confrontation between the two , though it soon abated . Failure . The Leviathan followed the Mon Calamari ' s trail , toward the Rangers ' base , with the Imperial shuttle in tow . Isen became very agitated during the long journey , continually querying Azard as to whether or not they had arrived at their destination ; the Quarren grew impatient with the repetitive questioning , and made as much clear to Isen . Eventually , they reached the base , and swarms of Krakana came out to meet them . The Mon Calamari avoided the Leviathan and instead targeted the shuttle , hoping that if they destroyed it , the creature would stop attacking them . The shuttle ' s shields held firm against the Krakanas ' plasma weapons , and since the Krakana were built for speed and had no shielding of their own , Isen thought the Mon Calamari ' s tactics foolish . Azard ordered the gunners to kill all of the Mon Calamari , and the transport began spraying blaster fire in all directions . Although the Leviathan targeted escaping refugees , the Rangers stuck firm at their task , searching for a chink in the shuttle ' s armor . However , the situation turned against the Sith when the Rangers ' ally , Imperial Knight Treis Sinde , arrived with many devilsquid s , which swarmed around the Leviathan and attacked . Azard formed a plan : the shuttle would release its complement of Shark fighters to deal with the Krakana , while it would deal with the devilsquids . Though the shields had to be lowered to launch the Sharks , Azard was confident that if the shuttle concentrated fire on the area of the launch they should be able to repel the Krakana . He was proved wrong , as a sole Mon Calamari ranger drove at the shuttle , committing suicide as she collided with the Imperial vessel . Isen ' s shuttle was crippled , and the bridge area disconnected from the rest of the vessel , which sank to the sea ' s floor . Isen escaped barely injured , but Azard was not so lucky , and was pinned to his chair . Using the Quarren ' s lightsaber , Isen freed him , and smashed one of the vessel ' s windows with the Force so that they could escape . Azard was surprised that Isen had freed him , but the Givin remarked that they were both part of the One Sith , and that Krayt would have wanted him to . The two then swam upward and away from the wreckage . Isen ' s creation , the Leviathan , was ultimately vanquished by Sinde and the Mon Calamari Rangers . The Final Protocol . Some time later , Lord Azard and Vul Isen received a holographic transmission of Darth Wyyrlok , who had taken control of the Empire and the One Sith in the name of Darth Krayt . Lord Wyyrlok told Azard and Isen that Emperor Krayt no longer wished to spend Imperial resources on the systematic extermination of the Mon Calamari and ordered Isen to execute the Final Protocol : the extermination of all life on Dac . Satisfied with the prospect of continuing his work elsewhere , Isen infected Dac ' s oceans with viral spore s , which would be carried by oceanic currents and kill every life form on the planet within a week . Three days later , Dac ' s oceans were already covered with the bodies of the dead . Isen ' s action caused the deaths of more than eighty percent of the planet ' s population , and would ' ve caused total extermination if not for the intervention of the Galactic Alliance Remnant and an evacuation fleet of civilian volunteers . The Butcher of Dac . After the genocide ended , Isen earnt himself the title Butcher of Dac for his crimes on Dac . Cade Skywalker , now waging a personal war against the One Sith led a team comprised of Jariah Syn , Deliah Blue and Wolf Sazen to Daluuj to find and kill Isen . This was based on intelligence provided by Naxy Screeger . A group of Sith Lords rushed out to meet the team and , while Syn and Blue rushed in to find Isen and set up explosives , Skywalker and Sazen fought off the Sith . Syn and Blue soon guessed that Naxy ' s intelligence was very old and that Isen was no longer on Daluuj . In fact , Isen was aboard the " War Hammer " , flagship of the First Sith Imperial Strikeforce , and had joined Lord Azard and Moff Rulf Yage to oversee the poisoning of Da Soocha , where Mon Calamari refugees had been granted sanctuary by Azzim Anjiliac Atirue . Da Soocha was infected with the same toxins as Dac while Da Soocha ' s moon , Napdu , was subjected to a massive orbital bombardment . Afterwards , Isen celebrated the victory and referred to Yage as the " Conqueror of Da Soocha " . Death . On Utapau , Isen , with Darth Azard at his side , set up a laboratory where he experimented on native Utai and Pau ' an subjects . The Givin planned to assassinate Gar Stazi and soon afterwards release a new plague , one that would adapt to any living species . Skywalker ' s comrades Jariah and Blue thwarted Isen ' s assassin , however , while Cade and Jedi Master Wolf Sazen confronted Isen and Darth Azard . Isen tried to run while Cade pursued . On the ledge Isen drew his lightsaber and engaged Cade . During the duel , both sensed Darth Krayt , who had returned from the dead , and soon after , Isen jumped into the sinkhole to release the vial . Cade leaped afterwards , and using the Force to propel himself to Isen , cut Isen in half before catching the vial containing the virus intended to purge Utapau , slowing it down and preventing it from shattering . As a result , Utapau was saved . Personality and traits . Born on Korriban and indoctrinated in the ways of the One Sith from birth , Vul Isen was not destined to become a warrior , but rather a scientist . He was naturally inquisitive , never accepting what he was told without proof , and often questioning the decisions and orders of his superiors . Isen believed that this attitude and way of being was integral to his success as a scientist . It did him no favors with other , more warlike Sith — unflinchingly loyal and unquestionably obedient to Darth Krayt — who believed Isen was not a true Sith . Isen was trained in genocide , and was adept at pacifying or annihilating entire populations . He saw it as something of a game , and took pleasure in his work . He felt that exterminating a species was less enjoyable than simply breaking their will , which he thought was a more subtle task . Despite this , the sadistic Givin worked extensively with viral type organisms that could wipe out entire planets and significantly alter their environment , and he liked to experiment with these organisms — on actual populations . He took great excitement in Darth Azard ' s plan to take out the refugees and the Mon Calamari Rangers in one fell swoop , and found the concept of the Leviathan ' s ability to absorb sentients ' life energies fascinating , even as he watched his beast reduce masses of Mon Calamari to nothing but empty shells . Isen was also quite talkative , unlike the reticent and taciturn Azard , with whom he spent much time on Dac . He often spoke of his preferences ; detailed his plans , and how he formulated them ; mocked other individuals , even his superiors , who had annoyed him or showed perceived incompetence ; and outlined the capabilities of his creation , the Sea Leviathan . He was impatient , and found it difficult to simply wait for something to happen . His mind required constant stimulation ; during the search for the Mon Calamari Rangers , he irritated Azard with his constant questioning as to whether they had arrived yet . Despite his inquisitive , independent nature , Isen was deeply loyal to Darth Krayt , his Empire , and its ideals . While Azard distrusted the Givin because he was not blindly obedient to his superiors like many of the Sith warriors , ultimately Isen showed his true colors to the Quarren Sith , freeing him from the wreckage of the crippled Imperial shuttle . This surprised Azard , who had expected Isen to merely save his own skin and leave the injured Quarren there , but Isen told him that Krayt would have wanted members of the One Sith to save each other , and that they must follow their master ' s orders . Powers and abilities . Isen ' s main skills lay in science , and he engineered a number of experimental deadly toxins in his time . He was also able to use Sith alchemy to create a Leviathan , altered for use in the sea , though the idea was not his own , stemming instead from Darth Wyyrlok , an expert in Sith lore . Despite being a member of the One Sith , Vul Isen was not destined to be a warrior . He himself admitted that he was never greatly skilled with a lightsaber , one of the reasons he did not become a " Darth " , and he did not carry a lightsaber in his service for Krayt ' s Empire . However , he did have rudimentary abilities with a lightsaber , using it to free Azard in the shuttle , and defend himself from Cade Skywalker for a short time . Though his focus was on research and bioengineering , Isen was still able to effectively wield the Force . Along with Darth Azard , he invoked the dark side on Dac to awaken the Sea Leviathan , sending his mind into the abyss where it was located and imprinting his will upon it . As they did so , a tangle of Sith lightning engulfed them . The Givin was also adept at telekinesis ; he used it to retrieve Azard ' s dropped lightsaber aboard the AT - AT on Dac , and used it to smash the vessel ' s window and create a means to escape . Isen was a capable swimmer , and was able to swim large distances because of his Givin physiology , which allowed him to survive in a vacuum . Behind the scenes . The character of Vul Isen was created by John Ostrander for the " " story arc of his " " comic series . Isen appeared in the of the arc in January 2009 , and subsequently appeared in the in February . In both issues , he was illustrated by Omar Francia .