22 Months After Endor (6 ABY)
Having been manipulated by Grand Admiral Thrawn through his human protégé Captain Pellaeon into an Alliance with the Galactic Empire, the Human Trader State (HTS) begins traveling from the Unknown Regions to the Inner Rim. There, the Triple Alliance, backed by several Rebel Strike Groups, are preparing to assault the vital world of Thyferra, the only producer of Bacta, the most vital medical supply in the galaxy. It is also the only fortress world between the invading forces and the Colonies, only one step away from the core worlds, and would leave the critical shipyards of Fondor vulnerable to direct attack.
Meanwhile, at the Mandalorian Capital of Keldabe, Boba Fett is declared to be the new Mand'alor. While the planet Mandalore is nominally claimed by the Rogue Warlord Zsinj, the Imperials abandoned the planet along with the evacuation of the Outer Rim and have not been present since. With Zsinj distracted by the New Republic and rival Grand Moff Ardus Kaine, he has yet to send a force to reconquer the planet, and most see Fett taking the rank as an attempt to strengthen Mandalorian morale and bargaining position.
23 Months After Endor
After several months of preparation, the combined Triple Alliance and Rebel allied fleets begin their assault on Thyferra, which they hope to be the first battle in the final campaign of the war. Led jointly by Admiral Ackbar of the Alliance and Admiral Yoshado of the TEC, the force included over one thousand warships, including Home One, 2 Ankylon Titans, an Eradica Titan and a Kultorask Titan. Defending the planet was Darth Vader on the Executor, the remnants of Death Squadron, the Super Star Destroyer Annihilator, and Admiral Piett on his new flagship, the Allegiance Battlecruiser Fealty, along with dozens of Golan defense Platforms and other battle stations. Unknown to the allies however, part of Grand Admiral Thrawn's fleet, including several Interdictor units, as well as almost the entire HTS armada, including two Ragnarov class Titans, lay in wait a micro jump away.
Unlike at Endor, the allies decided to bring in everything they had to try and overwhelm the Imperial forces. On the right flank, Admiral Ackbar commanded most of the starfighter units to begin attacks on the orbital defenses, while the center and left flanks engaged the Imperial Fleet. For the first hour, things appeared to go well, with the Imperial fleet falling back to the protective fire of the Executor Dreadnaughts, except for a heavy squadron of Star Destroyers and Interdictors under the command of Piett, which held their ground on the very left of the Rebel flank. Despite some concern from Ackbar, Admiral Yoshado could not justify holding back for a force too small to encircle his ships, and pressed forward.
About two hours into the attack, the Imperials sprung their trap. Using the pincer technique pioneered by Thrawn, the HTS-Imperial Armada warped right into the gravity radius being generated by Piett's Interdictors, which were perfectly placed to bring the reinforcements out of hyperspace directly behind the allied left flank. While the presence of more Trader ships caused some Rebel pilots to initially celebrate, the Ragnarovs instantly told the Triple Alliance all that they needed to know. Five years after the Sins factions stopped fighting to flee from the Vasari's pursuers, the truce was over. The old war was being resumed in a new galaxy.
Quickly realizing what the Interdictors were for, Admiral Ackbar immediately ordered a retreat, and Admiral Yoshado concurred. However, behind the HTS forces, which were rapidly moving to encircle the allied fleet, Grand Admiral Thrawn had brought in several of his own Interdictor units, and were moving to cut off the escape route of as much of the enemy fleet as possible. Ordering all strike craft to target the Interdictors, Ackbar managed to prevent them from encircling the center, allowing the allied right flank and center to escape (though the center came under heavy HTS fire). But there was no hope for the left flank. Caught with Interdictors on all sides, two Executor Star Dreadnaughts in front of them and two Ragnarovs behind them, the left flank could do nothing but fight to the end. The last ship to die was the Ankylon Titan Redoubt, which after exhausting her shields trying in vein to protect her comrades, had her antimatter tanks ruptured by a Ragnarov's railgun shell.
2 Years After Endor
Despite losing a third of its main fleet, the action was not over for the Triple Alliance. While the Empire's Human Trader State allies helped give them a victory, the HTS still needed worlds to resettle its population. The obvious answer was to take those worlds from the Triple Alliance.
Thus soon after Thyferra, the HTS began looking for weak spots in the Triple Alliance's boundaries, starting what would become known as the "Race to the West". Moving from Thyferra to the Galactic West towards the unknown regions, the HTS would start by outflanking the Triple Alliance left flank, engage them for a bit before the Triple Alliance countered by flanking the HTS's right flank, which the HTS would respond to by flanking the Triple Alliance's left flank, repeating the cycle. However, forced to leave a large force to keep the Imperials in check, the Triple Alliance could not quite send enough ships to keep the HTS from making gains to the galactic south, until finally the Triple Alliance could no longer afford extend their line any further. Within a month, the HTS finally broke through in the far south west of Triple Alliance territory, ironically occupying much of the territory first taken by the invaders, including Endor and Bakura. For the Triple Alliance settlers forced to leave their homes for the second time in as many years, evacuating in the face of the HTS advance was a most bitter experience.
25 Months After Endor
With their Triple Alliance allies under great pressure, the New Republic felt compelled to attempt a decisive action to bring momentum back to their side. The target that had to be taken was obvious to everyone; Rodia, the last pocket of the Empire in the Mid Rim that was squeezed uncomfortably between the Triple Alliance, New Republic and the breakaway forces of Ysanne Isard. While linking up the Triple Alliance and New Republic territories was a vital mission objective, it was assumed the Empire would have to retreat from Rodia without a fight if the core worlds were threatened. With the defeat at Thyferra however this was no longer a possibility, so with the heavy pushing of worlds close to the border, chief among them the Bothans, the Senate secretly voted to authorize the creation of a task force to attack Rodia.
Unfortunately for the New Republic, the Empire was informed of this attack in advance by an unlikely ally, Ysanne Isard. Having had several agents infiltrate the New Republic, Isard had shockingly accurate information about the planned attack, including its strength and likely leader, Bothan Admiral Layrn Kre'fey. While she knew Darth Vader would kill her if given the chance thanks to her failed assassination of the Sith Lord, a New Republic victory at Rodia would surround her territory, making it more likely that the New Republic and Triple Alliance allies would gang up on her. She thus ensured that data on the plan fell into the hands of a known Imperial spy, which she kept around just for such purposes. Within the week, Darth Vader sent Piett with reinforcements to Rodia to await the New Republic attack.
26 Months After Endor
In hindsight, the New Republic attack was doomed from the start. Layrn Kre'fey was good at political maneuvers in the Senate, which earned him his rank and command, but far less talented at maneuvers on the battlefield. Further, the New Republic military was only a year old; a handful of Rebel veterans were transferred to the new force, but most were new recruits or former members of planetary defense forces. While some of the New Republic vessels were brand new and of much higher quality than typical Alliance ships, including Kre'fey's flagship, the Bothan Assault Cruiser Kothlis, the crews were inexperienced, the bureaucracy inefficient, and even the new ships had not fully worked out their technical hiccups. And the old ships were often in worse shape than those used by the Rebels, having mostly been in local planetary defense fleets.
Thus while somewhat outnumbered, Admiral Piett and his forces were much more experienced, having been fighting for their lives against the Triple Alliance for two years. Further, at this point in the war the Empire still held a clear technological advantage over the New Republic ships, and Piett's forces were on the defensive, meaning the New Republic had to also engage Rodia's orbital defense stations. Keeping his forces in a tight battle line slightly behind the space stations, the Empire managed to beat back the under prepared New Republic attack with minimal casualties. The battle was perfectly symbolized when the Kothlis attempted to launch a volley of Proton Torpedoes at the Fealty, only to have them detonate prematurely due to a mechanical problem. Piett had the Fealty return the favor with a full barrage from its dual heavy turbolaser turrets; one of the blasts scored a direct hit on the bridge, killing Admiral Kre'fey. The battle had quite an effect on Layrn Kre'fay's grandson, Traest Kre'fay, who despite barely being out of the academy was serving as his grandfather's assistant. Forced to evacuate his once proud grandfather's flagship in an escape pod, Traest vowed to avenge his grandfather's death and restore his family's honor as a career military officer, not to use politics as a shortcut as so many other Bothans did.
The end result of these military engagements at the start of the second year of the Interregnum was the stabilization of the Empire's borders. For the next three years, despite continued major battles with the Triple Alliance, neither side proved able to take the increasingly fortified strongholds on the other side of the border. The New Republic and Triple Alliance had failed to join their territory, and while Imperial control of the space around Rodia was porous enough to allow the New Republic to replace Rebel casualties with new ships, trade had to be limited to the most vital commodities and joint operations were out of the question. On the opposite side of the galaxy, the Human Trader State was establishing itself in a slice of the galactic south west, making the Triple Alliance just as surrounded by enemies as the Empire. For the New Republic, the disastrous defeat at the Battle of Rodia caused it to lose any appetite for offensive operations. It would be years before it would be ready to mount such an attack again.