Battle of the Rishi moon / Legends A battle took place on the moon of Rishi in 22 BBY during the Clone Wars . The Confederate General Grievous and Dark Acolyte Asajj Ventress planned to attack the Wild Space planet Kamino in order to end the Republic ' s production of clone troopers based there , but a Republic listening post on the Rishi moon near Kamino prevented their fleet from entering the system undetected . Grievous therefore decided to capture the post before attacking Kamino to avoid alerting the nearby Republic fleet to his invasion . He deployed BX - series droid commandos to the moon in a boarding ship , and the inexperienced Republic troopers at the base failed to spot the approaching Confederate ship within a meteor shower . The battle droids then attacked the clones , taking them by surprise and hot - wiring the base ' s all - clear signal so that they were unable to send word to the Republic fleet of the attack . While the droids overran the base , clone troopers Echo , Fives , Hevy , and Cutup fled the base through a ventilation shaft . Outside , however , Cutup was killed by a Rishi eel . Meanwhile , Clone Commander Cody and Clone Captain Rex arrived for a routine inspection of the base . They were ambushed by the droid commandos but managed to escape and soon found the three surviving clone troopers . The clones then tricked the droids into opening the main doors of the listening post and quickly retook the base . When the commando droids stopped responding , Grievous sent a group of battle droids to investigate . Realizing that they couldn ' t defeat all of the reinforcements , the clones devised a plan to destroy the listening post with liquid Tibanna in order to shut off its hot - wired all - clear signal and warn the Republic fleet of the attack . Before they evacuated the base , however , Rex noticed that the remote detonator wasn ' t responding , so Hevy stayed behind to address the problem while the other clones escaped the base through a ventilation shaft . The invading battle droids entered the station ' s command center and opened fire on Hevy , injuring him . Hevy then manually detonated the explosive , sacrificing himself to destroy the droids and listening post to cut off the all - clear signal . Alerted to the attack , the Republic fleet arrived and intercepted Grievous ' s fleet , forcing the Confederate ships to retreat . Following the Republic victory , Echo and Fives were both inducted into the 501st Legion , and the late Hevy was honored for his bravery and sacrifice . Prelude . In 22 BBY , during the Clone Wars , the Galactic Republic began to utilize listening posts in the Outer Rim Territories to monitor Confederate activity . Due to the high amount of casualties suffered by the Grand Army of the Republic , new clone troopers were assigned to these stations without undergoing the customary intensive training most clones experienced before beginning duty . A number of these rookie clones , nicknamed " shinies " — a derogatory term referring to the troopers ' spotless armor that had not yet seen action in battle — were assigned to Rishi Station , a crucial listening post located near the Wild Space planet Kamino on the moon of Rishi , under the command of Clone Sergeant CT - 19 - 7409 , nicknamed " O ' Niner . " Seeking to end the production of the Republic ' s clone troopers on Kamino , the Confederate General Grievous planned to invade Kamino with the Dark Acolyte Asajj Ventress and a fleet of " Munificent " - class star frigates and " Lucrehulk " - class Droid Control Ships . However , Rishi Station played a key role in the protection of the area of space around Rishi and Kamino , and as long as the station was active , the Republic fleet would be warned of any Confederate activity in the area . In order to overcome this obstacle , Grievous decided to capture the station before continuing with his plan to invade Kamino . The battle . Confederate assault . Grievous deployed a squad of elite BX - series droid commandos in a " Droch " - class boarding ship to the Rishi moon to capture the base there . While the incoming pod hid within a meteor shower , the clone troopers inside the listening post raised the outpost ' s shields to avoid meteor damage . After landing with the meteors , the droid commandos emerged from their pods and stealthily made their way to the base , killing CT - 327 , a clone deck officer who was keeping watch outside the station , along the way . When the clones in the base lost contact with CT - 327 , Sergeant O ' Niner sent clone troopers Nub and Droidbait to search for him , but the two clones were quickly killed by the attacking droids . O ' Niner left the command center of the base to repel the invading droids and ordered trooper CT - 782 , nicknamed " Hevy , " to sound the alarm and alert the Republic fleet . The rookie clone trooper found that the signal was being jammed , however , and O ' Niner was soon killed by the battle droids . After witnessing O ' Niner ' s death , troopers Hevy , CT - 21 - 0408 , CT - 27 - 5555 — nicknamed " Echo " and " Fives , " respectively — and the trooper nicknamed " Cutup " fled from the base through a ventilation shaft inside the command center . Meanwhile , the leader of the commando droids contacted Grievous via hologram and informed him of their success . The cyborg general ordered the droids to leave the station ' s all - clear signal on , which , if turned off , would alert the nearby Republic fleet to the Separatist presence in the system . This kept the Republic oblivious to the attack and unaware of the incoming Confederate fleet ' s continued journey toward Kamino . Through a hologram transmission , Ventress reported to Grievous that she had infiltrated Kamino and that everything was ready for the invasion . Meanwhile , the rookie clone troopers emerged from the other side of the ventilation shaft and became situated underneath the listening post ' s landing pad . However , a Rishi eel appeared and grabbed Cutup before departing the area , further depleting the clones ' numbers . Retaking the station . Rishi Station , however , was due for a routine inspection , with Clone Marshal Commander CC - 2224 and Clone Captain CT - 7567 , respectively nicknamed " Cody " and " Rex , " being sent to inspect the base . After Cody contacted the base , a commando droid , disguised in clone trooper armor , answered the transmission . The commando droid told the clone officers that the base didn ' t need an inspection , but the clones were unconvinced , and continued to fly toward the listening post . They landed their " Nu " - class attack shuttle , the " Obex " , near the base ' s entrance , and were greeted by a commando droid disguised in clone armor . After the rookie clone troopers launched a droid attack flare , Rex noticed the flare in the distance and promptly shot the droid in the head . As Rex took off the clone ' s helmet , revealing that the clone was a droid , commando droids stationed behind the crates surrounding the clone officers emerged from their hiding spots and began to shoot at them . During the crossfire , the droids tossed thermal detonators at the clones ' shuttle , destroying the craft . However , the clones escaped the area by jumping off the landing pad . Cody and Rex found the surviving rookie clone troopers — Echo , Fives , and Hevy — and ordered them to take off their helmets , believing that they were droids in disguise . After the clones complied with the order , Rex began to address them with the derogatory " shinie " slang . When a Rishi eel again appeared , Rex quickly dispatched the creature with a single blaster shot to the eye . As the rookie troops seemed impressed with Rex ' s marksmanship , both clone officers took interest in the group and gave the rookies their DC - 15S carbine blasters . Rex devised a plan to infiltrate the base by pretending to be commando droid Unit 26 . While Cody , Echo , Fives , and Hevy waited on both sides of the listening post ' s entrance , Rex walked up to the blast doors ' surveillance systems . Commando droid units 07 , 08 , and 09 noticed that there was something different with Rex ' s vocabulator and ordered him to take off his helmet for identification . Rex took of his helmet but propped up a droid head in front himself to trick the droids into opening the door . When the commando droids opened the blast doors , the clones ambushed the droids and destroyed them , continuing on to ambush the other droids stationed inside the listening post ' s main control room . After retaking the listening post , the clones found that the commando droids had hardwired the station ' s all - clear signal . Meanwhile , Grievous noticed the commando droids were not responding to his transmissions . Suspecting that something was wrong , Grievous dispatched a group of B1 and B2 battle droids to investigate the listening post . Destroying the station . When the Confederate reinforcements arrived on the moon in a C - 9979 landing craft , Rex noticed that the new arrivals outnumbered the clone troopers and ordered the listening post to be destroyed , an order that surprised the rookie troops . After Echo recalled to the clone captain that their duty was to protect and defend the base , Rex dismissed his concerns , stating that if the base was destroyed , it would deactivate the signal and alert the nearby Republic fleet of the impending Separatist invasion . To destroy the base , Echo offered the use of highly explosive liquid Tibanna , which was used as a fuel source at the station when the Rishi moon entered its freezing cycle . While Rex and Echo went to retrieve the base ' s plunk droids that stored the liquid Tibanna , Cody , Hevy , and Fives grabbed weaponry from the listening post ' s supply room . Outside , Cody , Hevy , and Fives began to fire at the approaching droids . The clones tried to hold off the droids before they could enter the base , but the droids ' fire overwhelmed the clones and forced them to retreat back into the listening post . When the clones attempted to detonate the Tibanna inside the plunk droids , they found that the remote activator did not function properly . Hevy offered to stay behind and correct the problem before joining the other clones as they fled the listening post through a nearby ventilation shaft . After hearing the invading droids , Hevy left the control room and hid in an adjacent hallway to avoid detection . Meanwhile , outside the base , Rex found that Hevy hadn ' t yet evacuated the listening post . He contacted Hevy via comlink , but Hevy refused to evacuate the listening post until he was able to repair the detonator . Unwilling to accept Hevy ' s decision , the clones ran to aid the rookie trooper . Hevy , who had been hiding from the droids , utilized his Z - 6 rotary blaster cannon to fire at the battle droids . However , the droids managed to shoot Hevy in the leg , incapacitating him . Though Rex , Cody , Echo , and Fives attempted to contact Hevy via comlink while they ran toward the listening post , the trooper did not respond . Before they could reenter the facility , however , Hevy sacrificed himself by manually detonating the explosives . The listening post exploded , killing Hevy and destroying all of the droid forces inside . As the all - clear signal was cut off from the listening post , the nearby Republic fleet — under the command of Admiral Wullf Yularen and Jedi Generals Obi - Wan Kenobi and Anakin Skywalker — was alerted to the danger . The Republic armada cut off the incoming Confederate ships over the Rishi moon , and Grievous , realizing that his fleet was outgunned , ordered a full - scale retreat before the Republic could cause major damage to his ships . Aftermath . Shortly after the battle , a number of Low Altitude Assault Transport / infantry gunships were sent down from the Republic fleet to search for survivors of the engagement . On the moon ' s surface , the ships found the four surviving clones and returned them to the fleet , where Echo and Fives received medals for their bravery ; Hevy ' s sacrifice was also honored by the Republic . Rex then appointed the two rookies to the 501st Legion for their distinguished service in the battle . Rishi Station was reconfigured and replaced with a near - identical structure within a matter of days . Following the battle , the Galactic Senate issued a dead - or - alive warrant on Grievous , knowing that it was only a matter of time before he again targeted Kamino . Such was the case several months after the destruction of Rishi Station , when the Confederacy orchestrated another plan to invade Kamino ; both Grievous and Ventress were chosen to led the attack . However , due to Republic resistance , their attempt to destroy the cloning facilities and take control of the planet failed . Behind the scenes . The battle of the Rishi moon first appeared in the episode " Rookies , " the fifth episode of the series ' , which aired on Cartoon Network on October 24 , 2008 . " The Clone Wars " Director Dave Filoni used the battle to show that although commando droids were more useful than the basic B1 battle droids , a large force of B1s was still a threat . The explosion of Rishi Station was shown in the " newsreel " of the " The Clone Wars " episode entitled " ARC Troopers , " which was aired on September 17 , 2010 . The Rishi moon battle , as well as Rookies and ARC Troopers , were featured in the tie - in short novel , " " , that was released on October 7 , 2010 . The battle later received a non - canonical appearance in the " " video game .