In 18 BBY, the Grysk operative "Jixtus," who had allied himself with the Kilji Illumine nation, sent General Crofyp's task force to the Unknown Regions' Rapacc system to capture a group of refugees hiding on the planet Rapacc. The general's task force, consisting of Crofyp's Kilji war cruiser Anvil and Colonel Tildnis's Kilji picket cruiser Hammer, carried out an attack on Rapacc, confronting the Paccosh-commandeered Nikardun blockade frigate Aelos. Crofyp instructed the blockade frigate's captain, Uingali foar Marocsaa, to move aside and allow the Kiljis to capture the refugees they had come for; however, Marocsaa refused, prompting the general to prepare a cross fire attack on the Aelos.
The Anvil and the Hammer moved along the frigate's starboard and portside respectively, and once they were in position, the Chiss heavy cruiser Springhawk arrived at the outer system. The heavy cruiser fired two plasma sphere weapons at Crofyp's flagship before joining the confrontation in the inner system. The Chiss Senior Captain Mitth'raw'nuruodo, core name "Thrawn," instructed Crofyp to move clear of the Aelos, angering the general, who fired spectrum laser salvos at the Springhawk. Shortly after, the plasma spheres slammed into the Anvils starboard while the war cruiser shielded the Hammer so that the picket cruiser could escape. Thrawn allowed the Hammer to escape and destroyed Crofyp's flagship with breacher missiles.
In 18 BBY, the Grysk operative known as "Jixtus" sent several probes to the Unknown Regions' Rapacc system after he learned that a group of refugees he sought to capture had taken refuge on the planet Rapacc; however, the planet's natives, the Paccosh, chased the probes away. In response, Jixtus tasked a task force of the Kilji Illumine nation, with whom the Grysk had allied himself, with traveling to Rapacc and capturing the refugees and bringing them to a rendezvous point the task force's commander, General Crofyp, would specify. The Grysk hired two Pahtfinder navigators to bring the Kilji force to its destination; Qilori navigated Crofyp's Kilji war cruiser Anvil and Sarsh navigated Colonel Tildnis's Kilji picket cruiser Hammer.
During the cruisers' journey to the system, the Hammer slowed down, and Qilori stopped the Anvil so that the picket cruiser could catch up. Once Tildnis's flagship appeared near the war cruiser, the vessels resumed their journey, arriving at the inner Rapacc system simultaneously, confronting the Paccian Governance's Paccosh-commandeered Nikardun blockade frigate Aelos, which was orbiting Rapacc. Crofyp instructed the Paccosh captain, Uingali foar Marocsaa, to move aside and allow his forces to retrieve the refugees they sought; however, Marocsaa refused, prompting Qilori to make an attempt to peacefully resolve the situation, falsely claiming that the Paccosh, whom he believed to be Nikardun, could arise with the arrival of the Kiljis if they followed Jixtus's guidance. However, Crofyp revealed that the Pathfinder's claim was untrue and gave Marocsaa an ultimatum, commanding him to move aside or die.
Senior Captain Mitth'raw'nuruodo (pictured) commanded General Crofyp to move clear of the Aelos.
As the Paccosh commander did not comply, the general moved his warships for a cross fire attack on the blockade frigate, and the Anvil moved along the frigate's starboard and the Hammer did likewise along the starship's portside. Once the ships were in position, the Chiss Expansionary Defense Fleet heavy cruiser Springhawk arrived at the outer system, firing two vessel-disabling plasma sphere weapons at the starboard of Crofyp's command ship. As the spheres neared their target, the Chiss performed a microjump and joined the confrontation in the inner system; the Chiss Senior Captain Mitth'raw'nuruodo, core name "Thrawn," commanded Crofyp to move clear of the Aelos, the Springhawks prey, or suffer the "humiliation" of becoming collateral damage.
Enraged by Thrawn's command, Crofyp had his vessels fire three spectrum laser at the Chiss vessel after the Kilji task force turned to face the Springhawk. While the Chiss and the Kiljis traded laserfire, the Aelos moved to attack the Illumine's forces; however, Thrawn, seeking to confuse the Kiljis by fooling them into believing them that the Paccosh were allies or at least neutrals, fired a plasma sphere at the frigate to disable it. Marocsaa realized why the Chiss had attacked him and stopped his attack after launched a shuttle, stopping the plasma sphere.
Shortly afterward, the plasma spheres the Chiss had fired at the Anvil slammed into the war cruiser's starboard, disabling the vessel's weaponry, sensors, and defenses on that side. On the cruiser's bridge, the Kilji crew attempted to reactivate their weapons, but their efforts were thwarted by the Chiss, who destroyed those weapons. While the Anvil moved to shield the Hammer so the picket cruiser could escape, Qilori attempted to flee using an escape pod. Crofyp announced that they were not going to escape and remarked that the followers of the Illumine's Kilji way of order and enlightenment religion stood, fought, and prevailed. However, the navigator called the general a fool and fled in an escape pod. Several Chiss breacher missiles then destroyed the Anvil, killing Crofyp while Thrawn spared the Hammer, which fled.
The picket cruiser fled to the Unknown Regions' "Sunrise" system, where it kept station with one of Jixtus's Grysk warships. Thrawn rescued Qilori, bringing his escape pod to the Springhawk and tasking him with bringing the Aelos to the Hammers location by using the Force to track down Pathfinder Sarsh. The pair joined the Paccosh aboard the Paccosh frigate and Qilori brought it to Sunrise, where they boarded the picket cruiser and killed its crew before Jixtus's warship destroyed the Hammer and fled.
Shortly after the engagement, Qilori and the Aeloss crew traveled to the Sunrise system's planet "Sunrise," where Marocsaa told Qilori that as the Pathfinder had participated in the attack on Rapacc, he was a prisoner of war. After Qilori left Sunrise, he reported to Jixtus, telling him that the Chiss destroyed the Anvil at Rapacc and that Thrawn and the Paccosh boarded the Hammer at Sunrise.
The attack on Rapacc appeared in the 2021 novel Thrawn Ascendancy: Lesser Evil, the final installment of Timothy Zahn's Star Wars: The Ascendancy Trilogy.