Corps / Legends The Corps was perhaps the most useful and cohesive of the various high - level formations used by the Grand Army of the Republic and the Imperial Army — large enough to take most enemy worlds , it remained a key component in the armies of both the Clone Wars and the Galactic Civil War . It was also incorporated into the name of the Stormtrooper Corps . Grand Army of the Republic . In the Clone Wars , a standard Army Corps consisted of four Legions of Clone troopers , 36 , 864 men in total ; it was commanded by a Clone marshal commander and a Jedi General . Four Corps in turn formed a Sector Army . However , a number of formations that would strictly be subordinate Legions within these Corps also used the term " Corps " in their designations . This may possibly reflect their growth into autonomous units of Corps size on their own , but at least some of them remained part of their parent Corps even when called " Corps " themselves — making it often very hard to know whether a unit was a Corps or a Legion in terms of its place in the hierarchy , or its number of troops . In practice , the situation was probably very fluid , with various legions in various stages of evolution , with extra troops , increasing autonomy from their parent Corps , and new Corps designations of their own . One unit that was certainly a Corps was the 9th Assault Corps — because Commander Gree ' s 41st Elite Corps was one of its subordinate Legions . The 21st Nova Corps , the Galactic Marines led by Commander Bacara and Ki - Adi - Mundi , were also probably a Corps within the 4th Sector Army at some point in their existence , but the 327th Star Corps , led by Commander Bly and Jedi Master Aayla Secura , is officially a corps , as it includes the 7th Legion . Imperial Army . The Imperial Army was a much larger war machine than its predecessor had been , and composed largely of recruits from the civilian population rather than warrior clones . The white - armored elite troops who had been the backbone of the GAR had now been separated from the regular Army , and formed into a distinct arm known as the Stormtrooper Corps : as its name suggests , this was now organized as a single massive Corps , divided directly into component Legions , which could be assigned to Sector Group commands . Within the rest of the Army , however , corps - level units retained a significance comparable to that which they had held during the Clone Wars . Many corps had their headquarters aboard a massive KDY - Evkamar military transport , which served to coordinate subordinate units on various planets and warships across the sector , and a barracks for troops in transit from one assignment to another . The same ship could also carry an entire Corps into orbit for a planetary - assault deployment ; a single corps was regarded as a sufficient force to reconquer a planet that had recently thrown off Imperial rule , since it was expected for there to still be a significant Loyalist contingent and the Rebellion had not had the chance to reinforce their position . Typically the corps could expect to face odds of more than four to one , but regardless the Corps commander was expected to achieve local superiority and defeat the enemy in detail . A typical corps in the Imperial Army was still divided into four multi - regiment tactical formations , but these were known as Battlegroup s rather than Legions ; and often , these Battlegroups were reorganized from Divisions which had been under planetary or sector command in the days of the Old Republic . There were four standard types of corps - Line corps , Armor corps , Assault corps and elite Atrisian corps - and one corps of each type formed a standard Army . There was also the Corps HQs , which could function in an autonomous manner . A corps could also be augmented per their Order of Battle ( OB ) , in which case the additional units were commanded by the corps ' second - in - command . Line Corps . There were three line , one assault and one auxiliary battlegroup in a line corps for a total of 48 , 541 troopers , 20 , 658 support personnel , 2 , 599 repulsorlift vehicles and at least 371 heavy tanks . It could be expanded with a mobile battlegroup , two more line battlegroups , and an armor battlegroup . Atrisian Corps . Named after the famous Atrisian Assault Corps of the planet Atrisia that inspired the politics of the Empire , the Atrisian corps were among the elite of the Empire . Essentially assault corps they contained two assault battlegroups , a line battlegroup , an armored battlegroup and an auxiliary battlegroup , giving them 48 , 403 troops , 3 , 385 repulsorlifts and 795 heavy tanks . Fully - expanded Atrisian corps added a mobile battlegroup , a third assault battlegroup , a second armor battlegroup and a second line battlegroup . Armor Corps . This corps was suited for operations where firepower was more needed than agility . Three armor battlegroups , a mobile battlegroup and an auxiliary battlegroup gave the armor corps a strength of 48 , 192 troops , 26 , 602 support personnel , 5 , 128 repulsorcraft and 1 , 219 heavy tanks . Augmentation could double the corps numbers with three more armor battlegroups and a second mobile Mobile Corps . A mobile corps was the exact opposite of an armor corps : with its repulsorcraft vehicles the mobile corps could deliver fast strikes against rebel positions . Composed of three mobile , one armor and one auxiliary battlegroup , the mobile corps had a strength of 48 , 508 troops , 23 , 107 support personnel , 5 , 548 repulsorlift vehicles and 1 , 113 tanks . It could be augmented with three more mobile battlegroups and an assault battlegroup . Corps HQs . A Corps HQ of consisted a Major General and five staff officers ( SP1 - SP5 ) , each of whom had two staff officers of their own ( SP11 - SP52 ) , along with 388 support personnel , a security company of 156 troopers and six picket platoons under the command of major general or his second - in - command . The HQ was also burdened with three CompForce support platoons of 114 personnel total whose job was to support all CompForce units assigned to the corps , although their " support " was rarely adequate . Fifty ISB agents were also assigned to the corps HQ to ensure loyalty and provide intelligence , although it was the HQ ' s lone Imperial Intelligence agent who provided 15 to 20 percent of intelligence used by the corps . Finally the corps contained a huge number of droids , upwards of 2 , 000 in total from MSE - 6 mouse droids to I2F - 5 and I2F - 73 industrial droids . These droids formed the basis of an impressive industrial complex which could transform even the most crude and basic materials into anything from blaster packs to repulsorlift engine . So long as the complex was operating the corps could operate indefinitely . The corps HQ also formed the basis of the Imperial garrison of a world , which was why there were more corps HQs than there were corps in the Imperial Army ( beyond being very pleasant assignments for very average major generals ) . These garrison HQs served as organizing points for rapid mobilization , and in a crisis quickly took command of units as they were transferred into the theater of operations . Under normal circumstances , much of the garrison commander ' s duties were taken up with representing Imperial authority on his planet , and thus there were often civilians agents associated with the corps HQ including diplomatic , medical , trade , scientific and technical personnel . While nominally outside the major general ' s command in reality these agents often operated under his orders . The typical military contingent of these independent corps HQs was regimental in size , with four battalions of varying composition depending on the necessities of the situation . One popular configuration was a battalion of stormtroopers , two battalions of AT - ATs , and one of AT - STs . In addition the Ground Support Wing of an auxiliary battlegroup was always present , consisting of two TIE / gt squadrons , one TIE / sa bomber squadron and a TIE / fc spotter flight . Behind the scenes . This balance of forces would have given the Corps HQ garrison an impressive combination of firepower , armor , reconnaissance , and maneuverability for its size . However , it is hard to conceive of the nearly 200 tanks and almost as many support vehicles of an armored brigade fitting inside the prefabricated garrison base that was the physical presence of a Corps HQ , and the another Rebel source , discussing the garrison base in detail , implies a deployment of just ten AT - ATs and ten AT - STs . The same source suggests that a typical garrison ' s Ground Support Wing , nominally of 40 TIEs , comprised in practice three squadrons of whatever TIE Fighters were available , plus a flight of two TIE Bombers , with more bombers being added if the situation warranted them : this ties in with " The Imperial Sourcebook " ' s references to Army commanders having difficulty obtaining their correct compliment of TIEs , and adds weight to the evidence of this source ' s analysis . Turning back to the armored units , the smaller figures can best be interpreted as representing a single armor company , with three tank platoons where " The Imperial Sourcebook " speaks of three battalions : two heavy platoons of five AT - ATs each , and one light platoon of nine AT - STs , plus a tenth AT - ST as a company command vehicle . It is unusual to find heavy and light armor mixed in this way , however , and it is possible that these armor platoons were designed as cores around which larger units could be formed as required : three battalions would form the basis of an armor regiment , and with this in mind , we can note the 40 speeder bikes cited as part of the garrison , which suggest the presence of a scout troop that could serve as the basis of an armor regiment ' s repulsorlift battalion .