Viral spore Viral spores were deadly biological weapons developed by the One Sith scientist Vul Isen during the Second Imperial Civil War as a means of pacifying rebellious worlds without committing substantial Imperial forces . They were capable of poisoning all living organisms on a planet ' s oceans within days , effectively rendering it uninhabitable . These viral spores were deployed in canisters and were used to great effect as part of the Final Protocol as part of the Genocide of Mon Calamari on Dac . Later , Sith – Imperial attack ship s of Squadron Quad Victor deployed these during the destruction of Da Soocha . Description . Viral spores were a biological weapon created by the Sith scientist Vul Isen in 137 ABY , during the Second Imperial Civil War . Isen developed multiple strains of the viral - type toxin between 137 and 138 ABY , and each was capable of poisoning an entire planet . Once released into a world ' s waters , viral spores were immediately carried and spread by currents , killing every living thing that they encountered . Within one week , the entirety of a world , even one nearly completely covered in oceans , was affected , and nothing remained alive . Isen ' s initial viral spore formulas required multiple canisters full of the toxins to be inserted into a planet ' s waters . However , his final strain , which took the form of a light green liquid , was potent enough that a single vial — small enough to fit inside the hand of a Human or a Givin — contained sufficient destructive power for an entire world . Isen created the toxins as a means of punishing planetary populations who earned the wrath of Darth Krayt ' s Galactic Empire , an organization which the scientist served . He believed that the mere threat of their use would be able to pacify rebellion against the Empire . The different formulas were developed for use against various species , whose differing biological systems reacted uniquely to the toxins ' effects . Isen ' s original formula targeted the population of the planet Dac , a world which teemed with a vast variety of life , and his final strain was developed for use on the planet Utapau . During the latter formula ' s development , scientific experiments performed on test subjects from the native Pau ' an and Utai species helped Isen create a formula that would target both species . Although he was able to render himself immune to its effects , the scientist speculated that the third strain , which was adaptable , could affect any species in the galaxy . History . Vul Isen developed viral spores in 137 ABY while creating experimental viruses for use on the population of the planet Dac . Darth Krayt , Galactic Emperor and Dark Lord of the Sith , ordered a genocide of the world ' s native Mon Calamari in that year , and Imperial forces were sent to Dac to oversee their extermination . Isen and Darth Azard , both members of Krayt ' s One Sith , were dispatched planetside to lead the operation . Although Krayt ' s orders specified that only the Mon Calamari were to die , Isen created viral spores in the hope of poisoning the entire planet and wiping out every native species . To his end , he placed the spores in strategic locations throughout the planet and waited for the order to release them . After Krayt ' s servant Darth Wyyrlok attempted to kill his Master and usurped the throne , the new Regent of the Empire instructed Isen to release viral spores . Isen did so , and within three days , millions of Dac ' s natives had succumbed to its effects . The sheer number of corpses that floated to the oceans ' surfaces caused members of the starfighter unit Rogue Squadron to falsely observe from orbit that a new landmass had formed . When they realized that what they saw were bodies , they contacted their superiors within the Galactic Alliance Remnant . Alliance Admiral Gar Stazi organized a massive evacuation of Dac , and was able to ferry nearly twenty percent of the planet ' s various sentient species offworld before the effects of the viral spores encompassed the entire planet . The use of viral spores to poison Dac enraged many citizens of the galaxy , among them the former Jedi Cade Skywalker . Skywalker had recently declared a personal war against the Sith , and Isen , whom the former Jedi declared the " Butcher of Dac , " became his first target . Skywalker surmised that killing Isen and neutralizing his ability to create biological weapons would deal the Sith a considerable blow . While Skywalker hunted for his foe , Isen and Azard arrived at the planet Da Soocha aboard the Sith – Imperial Star Destroyer " War Hammer " . The Empire had learned that Azzim Anjiliac Atirue , a Hutt based out of Da Soocha ' s moon of Napdu , had recently given refuge to Mon Calamari refugees , and as such , Azard ordered viral spores to be inserted into Da Soocha ' s oceans while Azzim ' s spa on Napdu was bombarded by the " War Hammer " turbolasers . Insertion of canisters full of the toxin was performed by the Imperial bomber squadron Quad Victor .