Author's Note: This is meant to be an extremely heavy HFY in the sense that Humanity is the Empire. They will have the full force of thousands of Star Destroyers given that the Rebellion was very much decimated after Endor and with the almost non existent need for pacification the Empire can turn the force of it's war machine against the unsuspecting Council.
They will also have access to the First Order's technology given that it is hinted that many of the Imperial scientists and high ups who fled in the Canon Timeline to the Unknown Regions carried these secrets with them. However particular groups such as the Praetorian Guard and their Stormtrooper Corps or individuals such as Snoke or Kylo Ren will probably not exist. Likewise, the Reapers themselves will probably not exist simply for the ease of this story given that they are culling every fifty thousand years and given the Empire's almost technological dominance compared to them.
Do note as stated above, this is extremely heavy on the HFY!. If you do not accept this then this is not the story for you.
Disclaimer: I do not own anything related to any of the franchises. They are the sole property of Lucasfilm, Disney, Bioware, etc.
"Now witness the firepower of this fully armed and operational battlestation!"
At the same time Emperor Palpatine made his proclamation, Vader stood next to him, watching and sensing his son's despair. Skywalker's emotions flickered from anguish and sorrow to cold rage, his lightsaber fling itself towards his hand as he attempted to strike down the Emperor and with that, both the Emperor and Lord Vader smiled, for he had finally given into the Dark Side and the Empire, with the gain of one of the most powerful Force users had finally won.
3 ABY: The loss of the vast majority of Rebellion's military force is what breaks the back of the Rebellion, many of the remaining Rebels either defect to the Empire, break down into squabbling groups or pretend that they had no association with the Rebellion. The remainder simply go into hiding awaiting the day the Rebellion can be reborn. The Second Death Star however, puts an end to this, decimating Akiva simply through it's sheer number of forces onboard and destroying the planet of Tnasi when the Rebellion there attempts to hold the planet hostage as a bargaining tool. The Empire responds to this by evacuating as many Imperial allied civilians and troops as possible before the Rebellion inevitably takes the rest hostage. It is then that the Emperor, reluctant as he is, authorizes the destruction of the planet, finally bringing an end to the Rebellion as he foresaw years ago.
The Citadel Council welcomes the addition of the Turians to the Council itself after the staggering cost of the Krogan Rebellions, finally giving birth to the modern triumvirate that the Empire counters in the near future after the Council's futile attack against the newly inducted world of Shanxi.
4 ABY: The construction of the Second Death Star frees up numerous reserve supplies of materials, allowing for the construction of hundreds of new hulls. It is at this time, the plans for the new Resurgent class Battlecruiser are conceived, an attempt to further the Empire's supremacy over the galaxy. Director Roblin, head of the Empire's Advanced Ship Research division is placed in charge of the project.
Despite this, most of the new hulls are Imperial Star Destroyers with a small smattering of newer designs, improved to the extent that their Point Defence Arrays and heavy weaponry mean that they can forgo the need for smaller escorts dedicated to their defence.
The Citadel Council, still weary of the Krogan Rebellions allows the Turians to begin construction of their Vulture class Super Dreadnought. However the fact that only the Turian and their client races' economies are involved in the project means that the few warships capable of withstanding the Empire will take far longer than they can afford to.
5 ABY: At this point, the Empire has opened up thousands of once closed projects, including Thrawn's old TIE Defender project. With the economy and the stockpile of resources at an all time high, the TIE Defender's production is streamlined to an extent that within a few years, almost all of the TIE Fighters within the Empire are replaced with them. TIE Interceptors and Bombers are soon relegated to status as flight training craft.
Other TIE Craft such as the Phantom and Punisher soon see the light of day but despite this, many Phantoms are relegated to storehouses under the direction of the Emperor, nobody aside from the few privy to the Emperor's plans and visions understand why and many call for the Emperor to dispatch the fighters to them. A few disappearances soon fixes their perceptions. It is around this time that Sienar begins to develop the TIE Silencer.
The Asari, aware that should the Turians gain enough super dreadnoughts and dreadnoughts lay down the Treaty of Farixen as a way to restore the perceived galactic balance. Whilst this law does not extend to the Vultures themselves, the reduction of support ships they can field to protect the super dreadnoughts means that a single Vulture will cost nearly three times of it's previous cost given that Hierarchy doctrine states that each superdreadnought must maintain an escort of two Dreadnought battle groups at any possible moment.
The Salarians say nothing about this despite their weakened position in comparison to the Asari whose fleets have greater technological capabilities in terms of weaponry or the Turians whose massive fleet numbers allow them to maintain galactic security. It is well known unofficially that the Salarians advancement in their advanced stealth technology and "all knowing" information gathering means that they are the balance between the Asari and Turians. Neither side wishes to upset them should they favor the opposing side and potentially allowing them to assert dominance of their portion of the galaxy.
6 ABY: The drain on resources from opening up thousands of projects begins to strain the Empire. In order to counteract this, Emperor Palpatine authorizes the deployment of hundreds if not thousands of World Devastators constructed on Byss by Imperial Advanced Weapons Resource in order to strip mine the useless planets within the galaxy. The drain is fully reversed and the Empire, now standing at over thirty thousand Imperial Star Destroyers begins to expand rapidly, gobbling up as much territory as it can exert it's controls over.
Construction continues to increase exponentially, not only in the Navy but in the Army. By the time the Empire introduces itself the Citadel, they will not only have an advantage in their numbers but in their immense projection of both their Naval and Ground Strength.
The rapid construction of dreadnoughts and super dreadnoughts leaves numerous sites whose projected lifetime of mining had been reduced to a mere few years, dry of resources. With the Council forbidding relays from being opened, numerous wealth seekers attempt to chart for resources, very few find an untouched site of resources and those that do often attempt to extort immense amounts of money from the Council in return for the sites. The Council responds by dispatching Turian led armadas to the sites having had the ships tracked by the STG. Many of the sites are rapidly drained in the arms race.
7 ABY: The destruction of the research labs over Thanis forces Palpatine's hands, within the span of four months, Lord Vader leads a massive campaign of extermination, ruthlessly removing criminal organizations such as the Black Sun and the Hutts from existence. It is at this time that the Resurgent class finally goes into full production, Death Squadron receiving almost all of the new battlecruisers as reinforcements whilst a small minority remains in orbit of Coruscant and the planet of Praxlis, site of the Empire's advanced research divisions.
The Batarians begin their next wave of slavery raids, kidnapping and abducting as many civilians as they can. With the Council more concerned about each other and how they fair in the arms race many who see through the facade become disillusioned with the Council, given their descent into a bloated mass of supposed democracy that abuses its citizens in order to further their own agendas.
8 ABY: Peace is at an all time high, with crime rates having fallen significantly due to a lack of criminal organizations, a testament to Lord Vader's skill. Designs for the new Mandator IV Siege Dreadnought and quite possibly the largest warship to ever sail the stars are drawn up under Roblin's direction, personally ordered by Emperor Palpatine for the days and years to come.
The first production run of the Vulture Super Dreadnought is completed. By nearly breaking the back of the Turian economy the amount of Super Dreadnoughts is increased from one prototype to thirty six super dreadnoughts. It will take another Turian decade before their economy even recovers back to levels sufficient enough to resume construction.
10 ABY: Construction of the first Mandator IV Siege Dreadnought is complete. The Fulminatrix under Moden Canady undergoes it's trial runs at the Regulus Fleet Gunnery Range, not only obliterating the damaged Victory Star Destroyer assigned as it's target but the entire prefabricated base of a small pirate crew hidden within the asteroid field. TIE Silencers slowly begin production being reassigned to elite squadrons and special forces units as soon as they roll off the factory lines.
With Turian supremacy appearing to be nearly in their grasp, the Asari unveil their own Super Dreadnoughts, the Ascension line which not only exceeds the firepower of the Vultures but has far more efficient barriers and engines which allows them to outfight the Vultures.
The Salarians finally finish stealthing their fleet despite the construction of new hulls. In the war against the Empire, they are truly the only force that gives Emperor Palpatine cause for concern. With their stealth technology they can demolish supply lines and cause the blitz he is hoping for to turn into a long and destructive war of attrition.
11 ABY: The Empire's Imperial Star Destroyer line stands at forty thousand. With the hundreds of heavier warships that will back them up during the invasion, Emperor Palpatine knows that the Council's time is now ticking. They will have very few days to organize a force to respond to his invasion and with their policies and edicts carefully monitored to ensure that they are spread as thinly as possible it remains for the Empire to finish construction on the Supremacy class Star Dreadnoughts to truly demoralize the Council. With three on the line up, one for Emperor Palpatine to serve as the Eclipse, another to serve as Lord Vader's flagship and the last to be held in reserve, it will truly showcase the Tarkin Doctrine to the Council. Many of the advancements developed for the Army are unveiled, walkers such as the AT-M6 or the devastation provided by the Battering Ram Cannons ensure that any invasion will be completed by the Empire.
The Council's next wave of expansion occurs. Rather increasing the firepower or constructing newer dreadnoughts. They elect to construct gigantic fleets of support forces such as frigate or cruisers. Whilst this means any hostile force will need to spread more fire over their fleets to effectively engage them, the resources used in their construct ensure that the Dreadnoughts that the Council will desperately need to fend off the aggressive blitz of the Empire will need to be well protected and utilized to their maximum effectiveness.
15 ABY: Nothing of note occurs within the Empire at this time other then the continual construction of as many hulls as the Empire can afford to field. The Second Death Star now referred to as The Death Star is temporarily removed from service in order to update it to the latest possible technological advancements. As Emperor Palpatine's trump card he requires it both to ensure the destruction of Council's superiority and to ensure that he can enforce his rule over the galaxy. Upgrades that take two to three months are compressed to the span of four weeks without any flaw noticeable or work quality degradation.
The Council begins to prepare for the next wave of capital ship expansion, adding additional defences to Digeris, where the majority of the fuel supply of the Citadel Navy is located. It is believed to be an unassailable fortress with multiple super dreadnought squadrons and heavy weapon platforms protecting it. It's loss is what really drives home the fact the Citadel and it's races are all insignificant to the power of the Empire.
18 ABY: The ISD line reaches fifty thousand strong but as an aging design, it will most likely see the end of it's production within the next few years. Warships such as the Resurgent class or even the dozens of other rumoured designs are simply far more effective. They nevertheless still make up a good portion of the Imperial Starfleet and will probably serve many more years as the Empire's first line of defence. The construction of the Eclipse and Lord Vader's new Executor are finally completed almost a year ahead of schedule and at staggering costs carefully hidden from public view as much as possible. In the years at the Battle of Endor, military spending has risen to all time highs so much so that a full third of the galactic economy is invested within the Imperial military.
With this, Emperor Palpatine allows the ISD Judicator under the command of Commodore West to escort a science team to a forked shaped object near Shanxi.