The Conquest of the Chiss Ascendancy, sometimes more politely called "the Chiss Campaign", was a brief war between the Golden Empire and the Chiss Ascendancy that resulted in the Ascendancy being conquered and absorbed into the Empire. Though the war took only three months, it was the largest the Empire had yet fought and saw thousands of ships engaged between the two forces. The defeated Chiss were not entirely pacified, and would rebel during the Vagaari War six years later.
As early as the capture of the Vall`to sector in 102 ABY, the Golden Empire's expansion brought it ever farther in the direction of the Chiss Ascendancy. Knowing it was only a matter of time before the Chiss became aware of them, Rin Sakaros and her brother Tariun began planning a preemptive attack on the Ascendancy in 130 ABY.
The Royal Navy, already fielding over two thousand capital ships of various sizes, was ordered to step up production. Wartime taxes were instituted among the Empire's systems, and the additional revenue split between shipyard construction and personnel recruitment. The Empire added new Keltrayu-class heavy cruisers, braving the extra expense to add the ships' heavy weapon arrays to the Armada. The Royal Army added dozens of new cohorts, and the entire Armada engaged in numerous war games.
The Chiss remained unaware of the Empire's existence, with numerous light years separating the Empire's outlying systems and the border of Chiss Space. The Chiss were focused more on the possible threat of a Vagaari resurgence, having received intelligence to that effect. Meanwhile, the Second Imperial Civil War erupted and raged throughout the galaxy, furthering Chiss isolationism.
Tariun and Rin agreed that the Chiss Expansionary Defense Force posed the greatest threat to the Empire's invasion, and resolved to take out both major CEDF bases at once. They agreed that Tariun would take Rin, the Sith Star, and roughly forty percent of the Armada and attack Coreward Cormit, while Sorrik would take the remainder of the Armada to attack Rimward Kinoss. Fearing the Chiss intercepting her communications, Rin spoke to Sorrik telepathically instead.
The two enormous fleets, each over a thousand ships, decanted at Kinoss and Cormit within seven seconds of one another. Having foreseen that the Chiss would never surrender even if given the option, Rin dispensed with her normal requirement for her commanders to offer enemies the chance to submit. Instead, Sorrik deployed his fleet in the Battle of Kinoss while Tariun and Rin prosecuted the Battle of Cormit. Rin employed her Battle Meditation to break the will of the Chiss while her own forces sowed destruction among their ships. Sorrik, meanwhile, devastated the base and communications relays at Cormit.
With the two major CEDF staging bases in ruins, Tariun set his sights on Naporar, headquarters of the CEDF. However, with Kinoss and Cormit defeated, he knew the Chiss would place heavy defenses around Naporar. His fleet and Sorrik's streaked instead toward Csilla, the Ascendancy's capital. Both groups stopped repeatedly along the way to deploy gravity mines behind them hoping to slow pursuit from CEDF. They laced some of these hyperspace traps with actual mines to damage enemy ships and force more caution.
Meanwhile, the Ruling Families sent an emergency call for CEDF reinforcements deployed elsewhere in the Ascendancy or into what had once been the Empire of the Hand. Multiple fleets responded, but some remained on guard outside the Ascendancy to hold the line against possible Vagaari incursion, while others prepared defenses in the Redoubt.
The two Royal fleets united at Csilla and fought a battle against the CEDF there. Rin believed the fleet and her Force powers could overcome the Chiss resistance, but stuck to Tariun's plan; the Sith deployed his forces in seemingly haphazard configurations and retreated after a few hours of battle. A small detachment of the fleet hit nearby Avidich, destroying defensive emplacements seemingly just to be contrary before jumping again in the direction of Kinoss.
The Chiss leaders believed they had repelled the invaders, and took the attack on Avidich as a sign that the Empire was retreating to Kinoss, where it had attacked initially. The Nuruodo family authorized the deployment of additional defenses to Kinoss along with gravity mines of their own, intending to trap the enemy and destroy them. At the same time, ships and personnel were dispatched to Csilla to safeguard the capital.
In the Prime Fleet, hiding to galactic north of Csilla, Rin sensed her enemies' plans and authorized Tariun's followup strike. The fleet divided itself, with several hundred-ship battle groups conducting raids within the Ascendancy. Ool's farms and Rentor's aquatic cities were raided, though Chiss civilians were not harmed. Sorrik himself led a raid as far away as Noris, completely across the Ascendancy.
Rin could feel the surprise among the Chiss and the scattering of resources from Naporar to protect outlying colonies. When she intuited the Chiss were at their most vulnerable, Tariun led a massive attack on Naporar itself. In the Battle of Naporar, the CEDF force remaining at the planet was routed, with numerous ships captured. Rin authorized a brief invasion of the planet, and her attacking troops destroyed numerous CEDF relays and bases on the ground while looting and downloading the Chiss data archives not destroyed or wiped by the Chiss themselves.
After two days of battle and occupation, the Prime Fleet withdrew, the last ships vanishing into hyperspace just as major Chiss reinforcements were arriving.
Tariun dispatched his fleet again for more harassment, taking out defensive positions at Sposia and Jamiron, as well as sending a quarter of his force for a second attack on Cormit, where staging CEDF ships and repair crews were caught by surprise and devastated. Feeling the time had come at last, Rin and Tariun reunited the entire invasion force and returned to Csilla.
The Second Battle of Csilla raged for days, with the Armada fighting the CEDF force at Csilla and the reinforcements which steadily arrived. However, the Sakaros siblings had timed the attack perfectly; Csilla's own force was not enough to challenge the Empire, and its reinforcements arrived gradually rather than in a concerted wave, allowing the Empire to defeat them all in turn. By the end of the fifth day, Rin demanded the surrender of the Ruling Families, and they complied.
Legacy of invasion
You have no idea, Your Majesty, what you have set in motion. The Ascendancy is the gate that holds back a tide of horror you can not imagine. If we are gone, the galaxy will follow us.
—A deposed Chiss Aristocra to Rin Sakaros
The Chiss colonies surrendered quickly with most of the CEDF destroyed or captured. Rin declared a general amnesty for all who fought against her, releasing all prisoners of war and leaving much of the Chiss bureaucracy intact, though she removed the Ruling Families from power and installed Consuls over the Chiss worlds. The overwhelming majority of Chiss had no loyalty to the new government, but recognized that active rebellion would be useless, and opted to wait for the remains of the CEDF to rescue them.
The Armada suffered heavily during the war, with most capital ships at least lightly damaged. In addition, when the main fleets were dissolved and spread again throughout the Empire's territory, much of the Armada had to remain in the former Ascendancy to keep order and prevent rebellion. Royal technicians also struggled to quickly retask Chiss Star Destroyers and other captured ships for Royal service. The Armada was still rebuilding and trying to expand when the Tribulation began.
The CEDF commanders who were out of the Ascendancy during the attack pulled back and fortified themselves in the Redoubt. Rin was aware of the Redoubt's existence, but strewed gravity mines and explosives along the hyperlanes leading into it, opting to starve the rebels out rather than endure the massive casualties it would take to invade and defeat them. These forces sallied out to ally with the Chiss insurgents during the Chiss Rebellion six years later.