It is time that we bring an end to the New Republic's notion of superiority, an end to the death of billions of innocent sentient, an end to the Civil Wars.
—Zachary Palpatine to the Moff Council over a Holographic communication meeting.
The Decennial War was a conflict that took place in the aftermath of Operation Shadow Hand and the death of Emperor Palpatine, starting after the rescue of those civilians that had taken to hiding aboard the Sovereign-class Star Dreadnoughts Despot and Heresiarch where Palpatine's sons, Zachary Palpatine and Vincent Palpatine, were found having been transported there with the aid of Lumiya after she had freed them from captivity issued by her traitorous apprentice Carnor Jax.
Securing the Supply-line
Starting with Operation Breakout, the main priority of the Operation being the reconnection of the Deep Core Imperial worlds with those of other Imperial Remnant worlds, making a secret alliance with the Chiss Ascendency and using the secret Nebulae Unknown Supply-line that was formed by the Empire to supply Thrawn's missions in the Unknown Regions, Zachary managed to reopen supply-lines and communication channels with the new Imperial capital of Bastion.
The Success of Operation Breakout and the large number of raids coupled with the destruction of New Republic task forces near their territories, Zachary took Jerec's Super Star Destroyer Vengeance as his flagship, as the more powerful Sovereign was put to good use defending the Beshqek Shipyard that had been hastily constructed over the sun Beshqek in the Beshqek system in the Byss reconstitution plan. The Decennial War was finally met during Operation Revenge, while Admiral Gilad Pellaeon commanded the Executor-class Star Dreadnought Reaper and with Natasi Daala commanding from the Imperial I-class Star Destroyer Gorgon, Zachary commanded a assault upon the Shipyards and Supply-lines of the New Republic with the intent to cripple the Republic War-machine.
An end to the War
After the Space Battle of Anaxes that crippled the largest Republic fleet led by General Wedge Antilles in command of the Lusankya, the New Republic agreed to a political negotiation on Coruscant which was instead a plot by Leia Organa Solo to capture Zachary Palpatine in hope she can force the Imperial Remnant to surrender, this plan fails as Zachary revealed that he had planned for just such an outcome and revealed Operation Ceasefire's existence and the conditions of its enactment forming the Blockade of Coruscant.
The flawless strategy that made up the war allowed the Imperial Remnant to force a Ceasefire with the New Republic on their own terms and conditions, additionally the Imperial Remnant went on then to hunt down the remaining Imperial Warlords that hadn't fallen back into their ranks and to restore the Empire back to its former greatness, the war brought an end to both the Galactic Civil War and the Imperial Civil War before introducing the Imperial Modernization Program that soon caused the Remnant to christen Zachary Palpatine as their Emperor whom announced the reformation into the Second Galactic Empire.