Author's Note This serves as a bit of back story for my crossover fanfic so its written in a bit of an unusual style. Basically I needed a way to keep the Separatists around and to get their leadership halfway sane (the fact that I had to kill most of them off speaks volumes) in order to write the stories I wanted to. I've tried to keep it compatible with the canon Star Wars universe, but fair warning, I subscribe to more maximalist interpretations of the scale so there's going to be a lot of big ships and some pretty high numbers.
A Study of the Pivotal Action of the Clone Wars
There have been many conflicts throughout galactic history ranging from the epic to the absurd; however there have been few that have had the implications that the recent war against the Galactic Union has had for galactic civilization. Perhaps the wars against the Rakata are its equal as the technology gained from them opened up the galaxy to the victors. The war against the Union on the other hand opened up the possibility of infinite galaxies, but only if the participants can survive in the long run.
The Background
By now it has become well known where the Union originally came from even though the very possibility seemed outlandish during the period of the actual war. The Union originates from what can best be described as a parallel reality where time has advanced more than a century beyond our own. From study of the available records of their history, it is identical to ours up until the Union's invasion thus making their galaxy a potential future timeline of our own. Needless to say this has inspired a great deal of scholarship and interest in what presumably would have occurred had the Galactic Union not discovered other universes.
Much has already been written about the rise of Palpatine's Empire, its fall and eventual replacement by a second Galactic Republic, and the barbarian invasion from beyond the galactic disk. This information is old history to the Union and less carefully controlled than the history of their version of the galaxy closer to their present. The information involved there is much more fragmentary and reliant on hearsay but the story of the Union and their invasion can best be summarized thusly.
During the aftermath of the barbarian invasion the galaxy was in shambles and the government was discredited due to its bungling response to the war. It seems possible that it could have recovered, however the assassination on the head of the reformed Jedi order removed one of the few remaining forces for centralization in the galaxy. The order splintered over ideological lines and the power of the central government rapidly waned. Various areas declared their independence and within twenty years even most of the areas nominally under the control of the government were effectively independent.
This was a fifty year long period where in the majority of the galactic government largely devolved to the sectorial level. There were a few exceptions to this involving racially homogenous areas like Hutt Space however by and large galactic civilization had nearly collapsed. There were a mere handful of more powerful states remaining and it was from them that the new form of galactic government would rise.
The Core was less affected by the breakdown in authority than the other parts of the galaxy as the worlds there were far more interdependent and the polities could not fragment nearly as much. Initially the core was split into roughly four governments and when Tarus Epirus gained control of the dictatorship centered on the Kuat system he began rapidly to gain control over the entire Core region. In order to maximize his resources and minimize dissent he turned over control of the economy to massively powerful droid brains which as time went on took over more and more of the day to day business of running his nation. Within fifteen years he unified the Core and set his sights on recreating a galactic government. This goal was reflected in the name for the new nation that he proclaimed from Coruscant: The Galactic Union.
Under the reign of his son Teylassm the Union expanded to control most of the Colonies and parts of the Inner Rim; however it was at this time that the Union encountered a true rival for control of the galaxy. During the period of disunity a great deal of nostalgia for the ordered reign of Palpatine's Empire caused a number of states loosely based on that government to form around the galaxy. The strongest of these was the Second Empire centered on Eraidu. This empire attracted like minded governments to its fold and in the twelfth year of Tarus Epirus' rule unified a large portion of the rims of the galaxy under the rule of Garan Auldin a moderately powerful nobleman who had been trained by one of the successor organizations to the Jedi.
By the fifteenth year of Teylassm's reign the galaxy had largely been divided into thirds with the Second Empire and the Galactic Union each controlling one and the remaining third being split between minor nations and racial confederations. The Union had the majority of the galaxy's industry but comparatively few resources. The Second Empire was in the opposite situation but was rapidly expanding its industrial base via the use of self replicating factories. Both governments sought to rule the entire galaxy and it was clear that they would clash sooner rather than later.
The problem for the Galactic Union was that the strategic droid brains knew that they could not win such a war even if over two thirds of the minor states sided with them. The weight of resources and strategic weapons platforms favored the Empire too greatly. They could drag the war out for decades but it would be a loss nevertheless. Because of this inevitability the controllers of the Union's economy began funneling increasing amounts of resources into rather dubious paths of research. What was truly amazing was when one of these abruptly seemed to bear fruit in twenty eighth year of Teylassm's reign just as the Empire began to make concerted attempts to split the Union's Rim allies away from it.
At first it appeared the research had developed a portal into to the past, but after some surreptitious and very cautious experimentation the Union determined that the portal simply lead to an alternate reality rather than into their own past. With this discovery this freed the planners of the Union to undertake a bold invasion of a divided galaxy fighting a civil war with vastly obsolescent equipment. If the Union could defeat the forces of the waning Galactic Republic and fractious CIS they could gain the resources and industry to defeat the Second Empire.
The War
Upon realization of what their scientists had discovered, the droid brains that ran the Galactic Union wasted no time in jumping into action. With the superb intelligence granted by historical hindsight of records long since declassified and the rather ineffectual state of the galactic powers of their own past, the solution to the Union's resource problems seemed available. The combat brains established a war strategy of extreme speed and brutality and began scouting operations about halfway through the second year of the Clone Wars conflict.
Going into this war the Union had several major advantages. One of the biggest was that at the onset of hostilities they would have almost perfect intel on the Republic's forces and secret projects as most of these had been published during the reign of the New Republic. The second was that over the previous century during which combat levels in the galaxy had rarely dropped below widespread, the military hardware (droid soldiers, droid starfighters, capitol ships, and ground equipment) was battle tested and far better designed than the cobbled together warships of the Republic and CIS. Indeed, by the end of the Union invasion the CIS had largely stopped production of ships that had served it as front line vessels in the Union's timeline in favor of radically new designs as the older designs were little better than fodder for the Union warships. The Union also had a large contingent of Guaril soldiers, force using mercenaries who were one remnant of the old Jedi order. Their supernatural abilities and almost fanatical hatred of Palpatine would serve the Union well in their encounters with both the Sith's minions and the Jedi.
An additional factor in the Union's invasion also needs to be addressed and that is the general failure of Force based precognition in general and Palpatine's in particular. Records have shown that Palpatine was apparently one the greatest precognitives in history using his intimate knowledge of the future to manipulate both sides of a civil war to place himself firmly in power. However over the course of the war with the Union this power failed him as it did the Jedi, frequently only giving minutes of warning before major events instead of days or months as was typical (though throughout the buildup to the finale of the Rishi campaign the Jedi involved all had premonitions of the coming disaster). Theories for this failure abound but the most likely seems to be that as the Force from both realities interacted with each other it created massive amounts of psychic interference.
The Galactic Union also had several major disadvantages as well. The largest was numbers. They could not afford to devote more than a tiny fraction of their armed forces to this campaign nor any of their strategic weapons platforms lest the Second Empire sense weakness and invade before they were ready to respond. This was more likely than would first be apparent as both the Union and the Empire had extensive resources devoted to tracking each other's assets. Their tactics would have to revolve around rapid strikes relying on their warships' superiority to disrupt the enemy by demolishing their infrastructure and overwhelming isolated ships and flotillas. The Union also had to avoid pitched battle as much as possible; every loss would be nearly unacceptable as the entire purpose of this conflict was to increase their war making potential.
Their other big disadvantage was poor intel on the CIS. As the losers of the Clone Wars, there had been far less published on the forces of the CIS, this coupled with their decentralized nature meant that the Union's knowledge of the Confederacy was far more limited. In truth though, they were not nearly as concerned about this as they should have been as it was still unknown at this point by the Union's strategists how much the Sith influence had crippled the war making potential of the CIS, an influence that would rapidly fade as Palpatine's attention would soon be directed elsewhere. Indeed, as the initial thrusts of the campaign began several CIS projects that would have been disrupted by the Jedi at Palpatine's request had events continued unaltered proceeded unmolested as the Force users were sent to investigate the early actions of the Union invasion. Several of these projects would ultimately have important ramifications during the course of the war.
The scouting phase of the operations lasted for three months and largely went off perfectly. Their probe droids were largely undetected, and when they were they were easily mistaken for CIS scouts. Upon confirmation of the historical data in the Union's archives, the strategy was updated with minor revisions and the attacks were launched.
Due to the extremely limited numbers available for the campaign, the Galactic Union had to work hard to maximize their strengths. They biased their forces towards heavier ships, bringing in nothing lighter than a heavy destroyer (roughly equivalent to the Allegiance class vessels that would be introduced following the Clone Wars). By concentrating on heavy vessels and avoiding prolonged contact with the enemy the war droids hoped to limit their losses.
The entire campaign would consist of lightning strikes to destroy and disrupt the Republic and CIS's war making potential with a focus on shipyards and major industrial worlds. The majority of these targets ultimately would belong to the Republic due to a combination of better intel on these targets by the Union and an underestimation of the threat posed by the fractious CIS. Initially the strategic thinkers of the Union considered assaulting the hypermatter refineries of both sides. However despite the fact that neither side had targeted them thus far in their war with each other (the Republic intended to reclaim the CIS refineries for themselves and the CIS did not want to provoke the Republic into attacking theirs) both sides had them well enough guarded that the Union's planners did not feel it would be practical to fight through the equivalent of over 1,000 Lucrehulk vessels at each facility. As these strikes would be carried out vast automated factory vessels would expel the local powers from barren systems throughout places such as the Outer Rim and Rishi Maze and establish the infrastructure to feed the Union's war machine. The campaign would end when the Republic and CIS's war making potential had been eroded to the level where they could not significantly regroup and the barren systems were sufficiently secure from any potential attack.
The initial phase of the campaign went almost perfectly for the Union. They achieved complete strategic surprise, and their interuniversal gate facility's location outside the galactic disk made their home base impossible to locate. Their warships were superior to any warships produced by the CIS or Republic of the same tonnage (and their preponderance of large ships meant that only the newest designs of the local forces and the large short range battlewagons in the local system defense fleets could effectively engage the Union forces). Additionally the axial superlasers on the Union battleships meant instant death for any warship that got hit by them. The Union's droid starfighters with in some cases years of combat experience were capable of feats that only Jedi could duplicate, and their battle tested army was more than a match for the forces arrayed against them in the few widely scattered instances of ground combat. Many shipyards, fleet bases, and factory worlds burned across the galaxy as the Union struck each in turn with overwhelming force. As this occurred they began constructing the mines and factories in the outer portions of the galaxy largely unnoticed by the reeling Republic or CIS.
This is not to say that everything went entirely according to the Union's plan during this phase. As time wore on and their disruption to the galaxy increased they had to rely more on traditional intelligence gathering with a corresponding increase in uncertainty. Additionally, once it became clear what was occurring, the CIS and Republic took steps to safeguard their operations. The CIS primarily responded by moving them as they were all mostly mobile in the first place (and the Union's focus on the Republic giving them more time to do so). The Republic responded by pulling as much force as they could into the defense of strategic targets. This paid dividends, especially in the defense of Kuat. Kuat had been attacked early on, but the Union planners had underestimated the durability of the old Mandator system battleships. By the time they returned with a larger fleet the system was so well defended that any attack would be far too costly to bear (as the short Second Battle of Kuat proved with the loss of a heavy cruiser and 5 destroyers before the Union fleet could disengage).
During this portion of the conflict, the Jedi suffered grievous losses as squads of battle trained Guaril mercenaries fanned out across the galaxy hunting down the isolated Jedi. The Jedi eventually responded by forming their own squads while relying more on their clone soldier's support but large numbers of them continued to be killed throughout the conflict with only the most powerful surviving for any length of time in the field. Palpatine himself was too secure on Coruscant to attack in this manner; however the ostensible head of the CIS, Count Dooku was not. He managed to survive no fewer than 5 attempts on his life during this period, although he was seriously injured in the last one and lost most of his force using protégés during this time as well.
The final act of this first phase of combat was the Union's assault on Coruscant in an attempt to decapitate the Republic and strike a blow at Palpinism before it could establish itself in this galaxy as well. Ironically this battle occurred at nearly the same date as the Battle of Coruscant that had marked the beginning of the end of the Clone Wars in the Union's timeline. The battle lasted for only three quarters of an hour, but was extremely bloody despite that. It began with the Union fleet consisting of five battleships and assorted escorts emerging from hyperspace and firing their superlasers at the planet. Foresight from the Jedi (and the Supreme Chancellor) had enabled the planetary shields to be raised in time to meet the attack, but still the firepower of the Union warships was enough to knock the shields offline.
The local defense fleet moved to attack the Union vessels as a call for reinforcements was sent out as every Republic warship in the core converged on Coruscant especially as it became clear that the attackers were not running away upon meeting resistance as had been their standard procedure in every battle thus far. The Republic ships closed to point blank range to engage the union warships, in many cases physically blocking the larger ships from firing their turbolasers upon the now unshielded planet. It became clear at this point as well that as powerful as the Union ships were, their combat superiority was not as pronounced at such close ranges as they could not effectively concentrate their fleet wide firepower in such confined circumstances.
The Republic forces began to think that they might be able to finally win a decisive victory for the first time in this conflict when twenty minutes into the fight the Union battleship's superlasers had finished recharging. Only one fired at the planet, the rest took out the largest Republic ships facing the Union fleet, but that one was enough. The Senate, the Jedi Temple, and twenty trillion people were vaporized as a circle three thousand kilometers wide was bored into Coruscant's crust. Most of the planet's remaining population would die over the next few hours as the destruction from the shot propagated around the city planet. The Union ships, their mission accomplished, spent the next twenty five minutes fighting their way out of the general melee (though not without suffering losses of their own among their escort vessels) and then escaped into hyperspace.
While the Battle of Coruscant was a terrible loss for the Republic, it was not the decapitating victory that the Union had hoped for. The twenty minute respite before the planet was fired upon allowed enough time for Palpatine, the Jedi leadership, and many Senators to make their escape. The government was reestablished within the fortress system of Kuat as the war entered its second phase.
This second phase of the war saw far less destruction as much of the remaining primary assets for the CIS and Republic were too well defended or hidden for the Union to continue their destruction dealing assaults. The war became a series of lightning attacks on communications and shipping hubs as the Union attempted to disrupt the cohesion of their enemies. During this time, the defenders managed to rush several new (and highly experimental) ship designs into action, including some that wouldn't have been produced until late in the Galactic Civil War. The Republic managed several successful attacks on the Union resource nodes in the Outer Rim but continued to largely be on the defensive. During this time both the Republic (specifically the Jedi) and the CIS worked to discover the true nature of the Union invaders and to ferret out their strategy and any weaknesses. By the Battle of Auric Petain, the Jedi at least had begun to make a good deal of headway in this investigation.
While the CIS had suffered attacks during the war too, they had suffered comparatively less than the Republic did. By the time the second year of the conflict began the CIS had roughly the same amount of industrial power as the Republic, primarily due to the latter's losses.
However the comparative lack of physical devastation did not take into account the political disruption throughout the CIS. With Count Dooku incapacitated and many influential members of the Council dead (San Hill died with most of Muunilunst and Nute Gunray suffered a complete mental breakdown shortly before the Battle of Coruscant) the leadership of the CIS threatened to fracture. While the military remained under the control of the generals and admirals (and even gained in efficiency due to the lack of meddling by the civilian leaders) a lack of strategic direction saw the CIS largely defend its holdings and make small attempts at consolidating what they had gained throughout the conflict and connect their scattered territories with each other.
The political arm of the CIS threatened to split apart entirely with three main factions becoming apparent. The first, lead by Wat Tambor saw the Union's invasion as an opportunity and advocated attacking the Republic exclusively and possibly even allying with the invaders (despite the general lack of knowledge about them). The second which was energized by popular outrage over the destruction of Coruscant saw the invaders as an existential threat to galactic civilization and advocated suspending the war with the Republic or even rejoining them to fight this new foe. There was also a large faction who felt that either of two extremes proposed by the other two were going too far but had little in the way of strategy beyond continuing the status quo.
Most of the six months following the Battle of Coruscant was filled with political infighting as the two more extreme positions jockeyed for influence and support of the remaining ones. Eventually a moderate version of the unified front faction won out as the CIS decided to put their war with the Republic on hold until the threat of the Union had been neutralized. Tirae Unsira, the leader of a moderately influential avian species in the Outer Rim was chosen as the new leader of the CIS (largely because she was obscure enough that none of the other CIS members objected overly much to her nomination) as the generals largely sidelined the civilians in the Council in direction of the war effort. Diplomatic feelers were sent out to the Republic to negotiate a temporary cessation of hostilities until the Union's defeat, and it was a measure of the magnitude of the crisis facing the Republic that Palpatine eventually agreed to this (though he had his own plans for dealing with the CIS once the war was over as events would eventually prove). The CIS had finally dealt with the crisis in its government but the solution was widely believed by all the parties involved to be only temporary. Once the war was over they all planned to reform the CIS government on lines far more favorable to themselves.
The focus of the Union's intelligence gathering efforts during this part of the war was on finding where the new construction site of the CIS's Great Weapon was. This prototype strategic weapon had not been high on the Union's list of targets as it had not been anywhere near being completed by the time the Clone Wars had ended. Their delay in attacking it had given the CIS time to move the under construction weapon to the remote system of Auric Petain. Realizing the value of the weapon (and without Sith interference in its construction), the CIS made its completion their top priority as they began to move a sizable force to defend it. The Union also knew the value of the Great Weapon, and as time passed and hints of the CIS activity continued to be uncovered, they threw more and more resources into finding the hidden construction site. Their efforts finally paid off eight months after the Battle Of Coruscant when a probe droid located the system.
The Forces and Commanders
The CIS
Commanders
Duke Isidis: A member of the non Trade Federation Neimoidian rulership Duke Isidis did not conform to the stereotypes that were attached to this race. He was insightful and very intelligent and while not particularly daring was no coward. He had exhibited no desire to enter the corporate world and therefore had settled in to a position of civilian leadership on the purse world he inhabited. With little real power he spent most of his time studying military history and strategy which were of great interest to him. He eventually was considered by many to be an excellent if untested strategist and tactician.
When the Clone Wars began he offered his services to the newly formed separatist fleet and rapidly gained distinction as a good commander (especially when compared to the large number of incompetent or cowardly examples provided by his peers). He rose to some prominence before his string of successes began to negatively impact the Sith strategy and thus he was relegated to minor fronts in the war.
In the unaltered timeline that was where he had stayed until his death shortly after Order 66 was issued at the hands of an Imperial task force, however the need for good commanders led to his reinstatement to frontline service by the other CIS officers shortly after Count Dooku was incapacitated. He was placed in command of the regions around the construction site of the Great Weapon, and it was clear to him that it was by far the most important asset in the CIS arsenal. In effect his entire force was devoted to completing and protecting this asset, an asset whose importance only increased in the eyes of the other CIS commanders as the war continued. Isidis would be the commander of the CIS forces for this important battle.
Baron Sollas: A Geonosian weapon master he was placed in command of the Great Weapon's construction and originally the forces that were there to protect it. He was a strong supporter of Archduke Poggle and this support was what had landed him this position. While he had superb administrative skills, his military knowledge was rather lacking which ultimately resulted in Isidis gaining control of the military assets. In the unaltered timeline he had died with the separatist leaders on Mustafar, but here he would make a decision which would have far ranging impact.
Admiral Zi Tran: This Gossam was a distant relative of the leader of the Commerce Guild, Shu Mai and used this influence to gain a high rank and command of a Subjugator class vessel when they began to be produced. She was merely an adequate commander who generally relied on superior firepower and unimaginative tactics to win battles. She was usually quite worried that at some point someone would discover her lack of talent and have her removed from command so she was quite willing to attach herself to more competent commanders and rely on their thinking to lead her to victory. In the battle she commanded the group of Subjugators that were integral to Isidis' strategy.
General Grievous: This psychopathic cyborg was increasingly out of control as the war progressed especially when the incapacitation of Count Dooku and the death of San Hill removed the only two beings that had any real control of him. Fortunately for the galaxy he concentrated most of his violence on the forces of the Galactic Union and their Guaril mercenaries managing to gain several of their lightsabers as trophies. He had been a major advocate of continuing the war against the Republic but eventually acquiesced to the united front supporters. It was clear to all involved however that he had his own plans for the future of the CIS and they would begin to be implemented as soon as the conflict with the Union concluded. He ultimately played only a minor role in the Battle of Auric Petain.
CIS Military forces
The Great Weapon: This strategic weapons platform was still incomplete during the battle. Most of its secondary weapons were not installed, and while its primary weapon was theoretically functional it was untested and many of the support systems for it were not operational. Given the fact that it could not accurately target capitol ships anyway, it was widely seen as being irrelevant to the upcoming battle except as the target of the Union's attack. It was protected by a powerful shield generated from the planet, but the battle of Coruscant showed that such protection would only delay the Union fleet.
6 Skyfury battleships: These vessels were part of a design project to build significantly larger versions of the Lucrehulk specifically constructed as warships from the ground up thus avoiding the many problems their smaller cousins were saddled with. Major design changes over the course of the project, teething problems with the subsystems (especially involving the linkages between the Core Ships and the main hull eventually requiring the design of an entirely new, larger class of Core Ship), and Republic efforts at disruption and sabotage ensured that only a small handful had been built by the end of the Clone Wars in the Union's timeline. The ineffective nature of the CIS's smaller ships and the corresponding focus on large vessel research and production meant that these 10 kilometer warships, while not ubiquitous, certainly were making up a good potion of the CIS fleet's heavy striking arm by this point in time. They formed the core of Isidis' force and he commanded from the Impervious.
Cosmic Egg: This unique ship had been constructed by the Techno Union to defend one of its most important shipyards. It was an immense ovoid vessel over 20 km long with almost comically undersized engines. It maneuvered incredibly sluggishly and had only a token hyperdrive as it was intended never to leave the sector it was built in. It made up for this with powerful shields and a very large weapon compliment. Indeed, it was better armed than a Galactic Union battleship minus its superlaser. In the original timeline a group of Jedi had destroyed it before it could be completed, but the disruption caused by the Union invasion allowed it to be finished. Isidis had it towed to the new site of the Great Weapon's construction.
6 Subjugator heavy cruisers: These large ships armed with their flotilla disabling ion cannons were the pride of the CIS fleet and were still very rare despite the massive increase in their priority for construction after the Union invasion began. They were unique in that they were the only vessels produced by either the CIS or Republic that had weapons similar in scale to the main batteries on the Union battleships. This made them one of the few types of vessel that could favorably engage Union warships of similar tonnage to themselves. Isidis had to call in many favors to get these six vessels under his command and even then he had wanted more. They were an integral part of his plan to defend the Great Weapon.
52 Lucrehulk battleships: These converted freighters were normally the heavy core of CIS strikeforces, however for Isidis' battle against the Galactic Union they would serve as his primary line forces.
287 Providence destroyers: These were some of the better line ships being produced by the CIS during this phase of the conflict. The most well known member of this class was the Invisible Hand, Grievous' flagship in the original timeline. Against the Union they served as good escort vessels and auxiliary carriers. None of the smaller CIS capitol ships were particularly useful against Union forces so they did not play a part in Isidis' strategy beyond a swarm of communications frigates providing electronic warfare duty around the Great Weapon.
The Galactic Union
Commanders
Admiral Sol Arsanins: A human aristocrat from Kuat whose family had attached itself to the Galactic Union early in its rise and had therefore been richly rewarded. A fairly undistinguished student he had competently completed all the studies expected of a nobleman and had drifted into a position in the Union Navy where the organic commanders were becoming increasingly irrelevant. Not an ambitious man, he was content to enjoy the privileges that came with his exalted position. He was nominally in charge of the Union attack on the Great Weapon, but was more than happy to allow the fleet AIs to do all the work. The fact that a man such as him could command a force with such a successful battle record as his was a testament to the quality of the Union's military AI.
Battleminds Tempest, Star's Reach, and Firmament: These were the artificial intelligences which ran the three Union battleships that participated in the attack on the Great Weapon. They were the results of almost a century of dedicated research into command AI and suffered from none of the limitations of similar efforts undertaken by the CIS. They were good tacticians who knew how to use all of the resources at their disposal effectively. Their only weakness was that their tactics were extremely conservative (one might even call them timid when the orders to preserve Union assets if at all possible were added into their consideration) and they tended to prefer tactics that involved the minimal use of force necessary to achieve their objectives (this was normally only prudent but when faced with an enemy with unknown capabilities this could result in much delay as they attempted to determine what the minimum amount of force necessary would be). Under a competent commander, or when paired with other types of AI (such as the ones on board the Kylat class battleships in use by the Union) these limitations could easily be avoided, but under the lenient command of Arsanins certain flaws in their strategies would become apparent over the course of the battle.
Galactic Union military forces
3 Cosmos Battleships: These 19 km long behemoths were the design descendants of the Eclipse and Sovereign class vessels that were introduced during the galactic civil war. On their own they vastly outgunned most vessels in use during the Clone Wars and their axial superlasers could destroy nearly any vessel in one shot. They were the newest battleships built by the Galactic Union, and their relatively conservative AI was a reaction to the very aggressive AIs present on their predecessors the Kylat class battleships.
8 Dominant heavy cruisers: These 10 km long vessels would have been considered battleships in many previous eras of galactic warfare; however their lack of large scale weaponry such as superlasers made them heavy cruisers in the Union's navy. Their job was primarily to add weight to the battle line while being minor enough targets to avoid being attacked by the enemy's own battleships. Since during many battles in this war the battleships spent a great deal of their energy recharging their superlasers this scale of vessel tended to be the primary damage dealers in the Union fleet against enemy capitol ships.
25 Shroud light cruisers: These 3 km long vessels were the primary escort craft in lieu of the fact that the Union was avoiding the use of destroyer sized vessels for anything other than raiding for this campaign. They were fast, well armed and had extensive electronic warfare suites. Additionally this scale of ship had benefited the most from the increases in efficiency that had affected warship designs of the Union thus they were more powerful than their size would indicate. Despite being outnumbered more than 2 to 1 by CIS Lucrehulks, these vessels were more than a match for them.
The Battle
During the preparation for this battle, Isidis had extensively studied the actions of the Galactic Union forces during previous battles to get a good idea of their tactics. As he had no way of knowing which direction their vessels would emerge from and making the (accurate) guess that they would fire their axial superlasers on the Great Weapon as soon as arriving he stationed his fleet between the incomplete weapon and Auric Petain within the protection of the planetary shield generator.
The Union vessels behaved exactly as he expected, emerging from hyperspace and immediately firing their superlasers at the Great Weapon. As at Coruscant, this was enough to overwhelm the shields and permanently burn out the generator on the ground. Isidis knew that he had at most a half hour to defeat the enemy fleet. From a sheer tonnage standpoint this seemed more than possible, however by this point the superiority of Union warships was well known.
The first phase of the battle consisted of the majority of the CIS warships accelerating into a position midway between the Weapon and the Union fleet as Isidis sent word that the enemy attack had begun to CIS fleets in the area. As this occurred the incomplete Weapon was undefended and superficial damage was caused to its surface by the smaller Union ships. Admiral Tran's Subjugators took up position on either side of the Weapon and trained their ion cannons on the enemy fleet. As Isidis' ships reached their positions they were assailed by vast swarms of enemy droid fighters and as expected the Cosmic Egg drew the majority of the Union ships' fire and surprisingly took it quite well. Later analysis showed that the Union battleships were operating at well below their theoretical capacity as they devoted most of their reactor power to recharging their superlasers.
It was at this point that the core of Isidis' plan unfolded. The Union forces preferred to position themselves in a wide open formation with as many clear lines of fire as possible leading away from their heavy ships so as to maximize their long range firepower and concentrate it on specific targets. Isidis took advantage of this by having all six Subjugators fire on one target, in this case the Tempest. The Union battleship's shields were unable to withstand that amount of firepower and the vessel was immediately disabled. Isidis ordered his entire fleet to concentrate all weapons fire on the disabled enemy vessel.
Unfortunately for the CIS forces, the AI commanders of the Union fleet reacted quickly and physically blocked the CIS fleets fire by moving their smaller vessels in front of the stricken battleship before any serious damage could be done. With this respite the Tempest was able to recover from the ion blasts and moved itself further to the rear of the formation though most of the energy it had been building up for its superlaser attack had been lost.
As the Union vessels were recovering the Subjugators fired again, this time at the Star's Reach. The results were the same as the last time; however, the smaller Union vessels were much quicker at covering their stricken battleship. Additionally the Union forces dispatched about half of their light cruisers to destroy Admiral Tran's line of heavy cruisers. The rest of Isidis' fleet was unable to concentrate much fire on them as they accelerated towards the Subjugators as they were already heavily engaged with the main Union force.
Admiral Tran split her next volley of ion fire, sending half towards the approaching cruisers and half towards the Firmament. These three shots were not enough to overwhelm the Union battleship though the charge of the light cruisers was thrown into disarray as half their number were temporarily disabled. This was not enough however to prevent the remaining cruisers from engaging in battle with the Subjugators.
With more than half the estimated time until the Union superlasers would recharge gone and his strategy in pieces things looked bad for Isidis. His main fleet was taking increasingly heavy casualties as the Union forces chewed though his destroyer screens and his fighter squadrons were decimated by the superior Union designs. The Subjugator line was engaged in furious battle itself as the quick light cruisers took advantage of the ion cannons' limited field of fire to outflank the vessels. Isidis was about to order his fleet to close into a close quarters melee with the Union vessels where their superior firepower mattered less as had been seen at Coruscant when Baron Sollas acted.
The Geonosian had watched the unfolding battle with increasing unease and as Isidis' plan clearly began to fall apart he realized that he was probably less than ten minutes away from being killed by the Union battleships. Not wishing to go out when he was in command of the most powerful weapon ever constructed without even using it he ordered the Great Weapon fired at the lead Union battleship despite the very real possibility that the very act of firing could destroy the Great Weapon.
It therefore came as a great surprise to nearly everyone involved when the planet killing superlaser of the Great Weapon fired for its first time. The targeting was a minor miracle, managing to graze the side of the Firmament after penetrating a heavy cruiser that had been shielding it from any further ion fire. The glancing blow was enough to completely obliterate the Union battleship.
The surviving two droid brains in command of the Union fleet had no way of knowing that the Great Weapon could not fire again as that shot had burned out several important systems. Additionally the death of Admiral Arsanins left a major hole in the Union fleets command structure, for a critical time the fleet was thrown into confusion. While this did not impact the efficiency by which each vessel fought, the fleet immediately moved to a defensive posture and attempted to contact a higher authority.
It is possible that the Union strike force could have recovered from this blow, especially as they still had superiority in firepower and the Weapon could not fire again; however it was at this point that reinforcements arrived for the CIS defenders. General Grievous had been in the region preparing for an assault on a Union held world when he had received Isidis' call for reinforcements. He had jumped his fleet directly to the battle and had arrived in the proverbial nick of time.
The arrival of enemy reinforcements proved to be too much for the remaining Union AI's. The result of the battle had become too uncertain and they gave the order to immediately disengage and retreat. The remaining Union forces were able to withdraw with little trouble leaving behind a relieved if surprised CIS force.
Endgame
The immediate aftermath of the battle looked good for Admiral Isidis. He had inflicted the greatest losses suffered by the Union in a single battle thus far in the war. In addition to the battleship, the Union also lost slightly more than one third of their light cruisers and two of their heavy cruisers which was a similar proportion to what the CIS fleet had lost in the engagement. Isidis was able to leverage this victory into vastly increased prominence in the Confederacy military hierarchy and was able to triple his forces at the Auric Petain to guard the Great Weapon against the expected Union counterattack until he could have it moved to a new secret location. However the attack never came.
By itself the battle was strategically insignificant and had it happened in isolation the Union would doubtless have gathered enough forces to deliver overwhelming force and complete their objective. However the culmination of the largest Republic counteroffensive was occurring simultaneously at the world of Rishi.
The Rishi Maze had been seized by the Union early in the war and had become a center of their mining and automated factory construction efforts. The world of Rishi guarded the easiest route into the satellite galaxy and served as a staging area for Union vessels making attacks throughout the "southern" quadrant of the galaxy. It was here that both Palpatine and the Jedi council chose to make their first major counterattack against the invaders.
An enormous force under the joint command of Jedi Master Windu and Palpatine loyalist Wilhuf Tarkin had attacked the Union forces in the Rishi area nearly two months previously and had ground their way slowly towards the system. After a series of hit and run battles around the planet and an epic ground campaign the final droid forces of the Union were destroyed on the planet's surface a mere four days after the battle of Auric Petain. Plans were drawn up to begin the liberation of the Rishi Maze and locate the center of the Union's war effort (as it was still unknown at this point where exactly they were coming from; it was still assumed that they were invading from outside the galaxy).
The Galactic Union at this point faced a major problem. By no means were they losing the war, they still had vast numbers of ships and war material back in their home universe, however the use of these would weaken them against their Second Imperial foes. They could likely drag the war out against the CIS and Republic for over a decade and cause massive casualties but their failure to knock out either of them meant that they could not win with what they had committed to the campaign. It was clear to the droid brains that made strategy for the Union that they would have to take a major risk to end the war favorably.
So it was that they gambled that they would be able to dispatch a strategic planet destroyer to end the war before the Second Empire would notice its absence. A mere three weeks after its recapture, a Union superlaser platform (which was a design descendant of the failed Hutt Darksaber project rather than the CIS Great Weapon), arrived in orbit of Rishi escorted by a major fleet containing ten battleships and their assorted escorts. It paused just long enough to withstand the firepower of the massive Republic fleet gathered in orbit of the planet and to allow the world's shields to be raised, and then destroyed Rishi. Nearly all the forces that the Republic had committed to the attack were lost in the resulting blast including both commanders.
Immediately after this display of strength the Union contacted both governments and requested that peace negotiations begin at once. It was clear that the unspoken threat was that the Union would then continue to destroy worlds one by one until the Republic and CIS agreed to its terms. This was however a massive bluff, the Union had returned the superlaser platform to their home space and would not risk sending it back into battle in this campaign.
Individuals in both the CIS and Republic, which following the initial victory at Rishi had begun reorganizing itself into an empire, quickly saw through the bluff. Based of their destructive tactics used throughout the war it was obvious that if the Union had always had the capability to use such weapons they would have. Obviously they were nearing the limits of what they were willing to risk in the conflict. However, despite this both Palpatine and the CIS council thought they had more to gain than lose in negotiating a peace treaty. The CIS believed that any such treaty would result in an effective end of their war for independence on quite favorable terms for themselves. Palpatine who was as always a master opportunist was hatching a plan that not only would give him total control over his new Empire and the CIS but would also turn the entire galaxy against the Jedi. So it was that a mere seven weeks after the battle of Auric Petain the three main belligerents met amongst the rubble of Rishi to discus peace.
The Conference and Aftermath
Teylassm Epirus himself led the Union delegation to the conference and set the tone for the heads of the other delegations. As per his plan Palpatine led the soon to be Empire's delegation and his pawn, the still injured Dooku led the CIS group. Isidis would be in charge of the CIS forces security, a decision by Dooku that would leave the easily manipulated Grievous in place to unwittingly complete his part of Palpatine's master stroke.
Over the course of the negotiations the truth about the Union was finally revealed which caused no small amount of confusion in the galaxy at large. Teylassm's terms were harsh, the Union would keep everything they had taken, but Palpatine acquiesced fairly readily as it was clear to many that there was little the Republic could do short of returning to war to gain the territories back. What was surprising was how easily he submitted to the CIS's negotiating points which left the confederacy in control of almost a third of the galactic disk. As he was planning to regain control of these areas anyway as part of his plan Palpatine was quite willing to cede control of them over to a government that would soon cease to exist.
It was at the final signing ceremony that his plan finally came to fruition. The Jedi, already concerned by the increasing autocratic direction the Republic was taking were spurred into action by Palpatine taking the opportunity to declare the reorganization of the Republic into the Empire during the pre-ceremony speeches. If that was not enough information revealing him as the Sith lord Darth Sidious made its way into the Jedi's hands at this point. The Jedi, backed against a wall, decimated from the galactic conflict believed they had no choice but to act immediately to save freedom in the galaxy. Despite deep foreboding the remaining Jedi set off immediately for the rubble of Rishi to take Palpatine down.
At the same time his agents made public to Grievous the disquiet the newer members of the CIS council had concerning the cyborg and heavily implied that they were planning to have him eliminated. He reacted to this information very predictably and launched his forces against the council's hidden headquarters. If he had been successful that would have left the unstable (and easily killable by Palpatine's agents) general as the sole leader of the CIS. However this was where the new Emperor's plan began to unravel. Isidis had never trusted Grievous and had left contingency plans in place for just such a coup attempt. The general died as his fleet was struck from behind by the very forces that had won the victory of Auric Petain under the command of Admiral Tran before he could breach the defenses of the council's fortress on the isolated world of Mustafar.
However Palpatine's plot involving the Jedi went much better from his point of view. They arrived in the midst of the signing ceremony. Using the Force the Jedi were able to penetrate the defense cordon around the station where the ceremony was being held. On view live to two galaxies they cut their way through the guards surrounding the delegates and levied allegations at leader of the Republic, Palpatine. They attempted to take him into custody or kill him, witnesses cannot agree on which. What truly happened next no one can actually agree on and the camera feeds all went blank at this point, however it resulted in the death of Count Dooku, the injury of both Epirus and Palpatine and required the intervention of both Admiral Isidis' crack commandoes, a platoon of Guaril mercenaries, and a betrayal of the Jedi order by Anakin Skywalker to drive the few Jedi who survived the ensuing fight away.
The peace treaty was almost scuttled by these events, however it was believed by all involved at the time that the Jedi had been acting as rogue agents and the treaty went forward though Epirus made some cryptic remarks about the true face of the Republic being made visible. Palpatine easily painted the few surviving Jedi as dangerous rogues that had almost plunged the galaxy back into war and began the process of creating his Sith theocracy (which with two outside threats evolved far faster towards his final goals than in the Union's timeline).
The CIS was in turmoil and for several years it seemed as though it would not survive. However, under the surprisingly able leadership of Tirae Unsira and the unflagging efforts of Isidis enough stability was reached for the Confederacy to create an actual constitution and government for itself though it still remains to be seen if either will last. Both the Empire and the CIS have devoted immense resources into matching the Unions war machines and both now have several strategic superlaser platforms and have begun producing the first warships that can go toe to toe with their Union counterparts. An additional focus of research in both the Empire and CIS is the same technology that allowed the Union to reach them in the first place though they have yet to duplicate it as of yet.
As for the Union, it spent ten years building up its industry and military forces in its newly gained territories. From what little information has filtered across from their universe, the Union launched a surprise attack on the Second Empire seven years ago and seems to be winning. Estimates are that within a decade they will control their entire galaxy and may seek to finish what they began during the Clone Wars. If the galaxy can withstand them a second time remains to be seen.