Ghost Prison incident The Ghost Prison incident was a military coup that occurred in the early days of the Galactic Empire ' s reign . The coup was orchestrated and instigated by Gentis , the Headmaster of the Imperial Academy and a hero of the recently - ended Clone Wars . After serving Supreme Chancellor - turn - Galactic Emperor Palpatine through the Clone Wars and the early Imperial Period , Gentis grew weary of war and angry over the continued deaths of thousands of young Imperial soldiers . In 19 BBY , Gentis resolved to betray the Imperial establishment by enlisting the first class of Imperial Academy graduates in a conspiracy to overthrow the Emperor and seize control of the Empire , thereby putting an end to Palpatine ' s destructive campaigns of oppression and expansion . The coup began on the Imperial capital world of Coruscant , the evening of the Academy ' s graduation ceremony . Gentis - allied saboteurs and bomb ers detonated explosives at critical targets throughout Galactic City , while the Empire ' s newest class of officers disguised themselves as terrorists and attacked stormtroopers outside of the Imperial Palace . Meanwhile , Headmaster Gentis and several of his most trusted students personally met with Emperor Palpatine in his throne room , where they detonated bombs containing the deadly Aorth - 6 virus . The bioweapon quickly killed all of Palpatine ' s defenders , but the Emperor was spared from death by his own Force abilities and the intervention of Imperial Moff Trachta . Although Palpatine ' s apprentice Darth Vader and the loyal Lieutenant Laurita Tohm defeated the attackers outside of the Palace , the Emperor ' s weakened condition and Gentis ' s influence on Coruscant forced the loyalists to flee the planet . Darth Vader and Moff Trachta agreed to take Palpatine to a location far removed from Gentis ' s influence . Calling upon his past experience as a Jedi , Vader suggested The Prism , a secret prison facility previously maintained by the Jedi Order and entirely unknown to the rest of the galaxy . Vader , Tohm , and Trachta ferried the Emperor to The Prism , where he was rehabilitated ; meanwhile , Gentis consolidated power on Coruscant and moved forward with his plan to seize total control . Given that he was uncertain of Palpatine ' s survival , he maintained the facade of a terrorist attack and instead decided to target Grand Moff Wilhuff Tarkin — one of the Empire ' s most prominent military and political leaders and the head of the secretive Death Star project . On The Prism , Vader and Tohm hatched a plan to retake Coruscant by recruiting an army comprised of the prisoners in the facility . After instigating violent riots to cull the weak and find the strongest of the inmates , the Imperials selected thirty - three former criminals to pardon and reform into a pro - Palpatine fighting force . Their plan reached fruition when the loyalists were able to intercept Grand Moff Tarkin ' s shuttle " en route " to Coruscant and confront Gentis . A fierce battle erupted between Palpatine ' s forces and the insurgent officers upon the shuttle ' s arrival on the planet , but in spite of the revolutionaries ' superior numbers , they were quickly overcome . Emperor Palpatine personally killed Headmaster Gentis during the battle , finally ending the coup and reclaiming Coruscant . In the aftermath of the conflict , later dubbed the " Ghost Prison incident , " the surviving conspirators were rounded up and executed by firing squad and the events of Gentis ' s coup were deemed classified by the Imperial government . Trachta and Tohm were promoted to the positions of Grand Moff and Admiral , respectively , and the remaining prisoners from The Prism were killed . History . Origins . In 19 BBY , a few weeks after the rise of the Galactic Empire , General Gentis attended a military meeting on Imperial Center . While seeking to escape the droning of the various Moffs , he discovered the Imperial Crematorium , and watched hundreds of dead Imperials be incinerated every minute . Realizing that even though the war had ended , the Emperor ' s warmongering ways would never cease , he quickly set about seeking a way to end the senseless killing . The fact that the Emperor ' s warmongering ways also cost him all of his sons except for Caul only solidified his desire to end it . The first class . A few months later , the cadets of the graduating class of the Raithal Academy arrived on Coruscant . They were part of six different academies from around the galaxy who came to the capital in order to be part of the first graduating class of Imperial officers . Their training — like that of the Empire ' s clones and other military personnel — had been accelerated from the usual years to only a few months . Gentis , a hero of the Clone Wars , presided over the ceremonies . Laurita Tohm was the valedictorian of the Raithal Academy , and thus was given the rank of lieutenant by Gentis himself . Tohm was soon selected to be a part of Grand Moff Wilhuff Tarkin ' s fleet , but Gentis had other plans for the young officer . He ordered Ensigns Caul and Shens to keep Tohm " out of harm ' s way " . Tohm ' s friends locked him inside a prototype Imperial Starfighter , and for a time , he assumed it was a practical joke . In reality , this was the first small step in Gentis ' s coup , as he believed that the promising officer would draw too much attention due to his prominence and deformities . Gentis , in truth , cared deeply about those he trained , and orchestrated the coup in part because he knew their new Emperor would never cease throwing Imperials to their deaths . The usurpation of Coruscant . Explosions rocked the cityscape for kilometers around , eliminating seventy - two Imperial targets within minutes . The officer ' s club , various Stormtrooper garrisons , the Comm Towers , and a supply depot were all destroyed . Imperial Plaza became ground zero in the battle that erupted , as " terrorist " forces swarmed through the city streets , fighting with the Empire ' s clone forces . The stormtroopers were losing the battle until Darth Vader appeared , rallying the troops and driving the enemy forces back . In the madness , Tohm had escaped from the prototype starfighter by engaging its ejection seat and landing in the midst of the battle . Tohm joined the stormtroopers in following Vader , but when one of the terrorists grabbed his ankle , he bent and removed the man ' s mask , revealing his friend Shens . Shens begged Tohm to help them kill Palpatine , the main target of their assassination attempts that night . As Shens lay dying , he then asked Tohm to kill Vader , but Tohm told his friend that he should have included him earlier , and shot Shens in the head . Tohm then bowed to Vader , who instantly respected his bravery and loyalty . As the pair made their way from the plaza , another explosion tore through the nearby buildings , unleashing a powerful necrotic virus known as Aorth - 6 . Dozens of Imperials , including Royal Guardsmen , were killed by the aerosolized virus , which liquified them from the inside out . Tohm donned a breathing device that he had taken from the TIE fighter when he ejected and followed Vader inside . There they found a mortally infected Palpatine and Moff Trachta . Palpatine was using the dark side of the Force to keep the virus at bay , but was losing the battle even with his formidable powers . Vader accused Trachta of being in league with the conspiracy , but the Moff vehemently denied it , saying they needed to get the Emperor into hiding ; fear of his power was the only thing keeping the Empire together . The trio escorted Palpatine to secret hangar below the Imperial Palace , where they loaded him aboard a stealth transport . The Prism . Using information gleaned from the Jedi Temple ' s High Council Chamber , Vader deduced that the only safe haven for the sick Emperor was at the Prism , a prison facility located near Diab ' s sixth moon at the Diab system that was kept secret by the Jedi Council from even the Supreme Chancellor . Lacking loyal or trustworthy soldiers , Tohm suggested to Vader that the prisoners of the Prism be released and allowed to fight for them , which would allow them to retake Coruscant from General Gentis . Vader amended Tohm ' s idea , and rather than simply releasing the prisoners , he forced 207 of them to fight one another , as well as Tohm and himself , for the right to serve the Galactic Empire . The battle was vicious and wild , with casualties mounting quickly . Separatist sniper Shonn Volta allied herself with Tohm after saving his life from General Ur ' Loach , while Vader defeated Nax Cirvan , a fallen Jedi , who then submitted to the Dark Lord . In the end , only thirty - three prisoners survived in fighting condition , including Volta and Cirvan . Vader ordered Trachta to tell the survivors what it meant to serve the Empire . Trachta told the survivors that their crimes were now forgotten , but their reasons for committing them were not — they would now serve an institution not beholden to the " selfish " senators of the Republic , nor the Jedi Order . The prisoners knelt before Trachta and the others , becoming Imperials through their submission .