The Hammer was a Kilji picket cruiser commanded by Colonel Tildnis, who served the Kilji Illumine, the nation of the Kilji species. It was armed with spectrum lasers and equipped with a main drive, a hyperdrive, and a tractor beam. The picket cruiser was one of the two Kilji cruisers in Illumine General Crofyp's task force, the other being Crofyp's Kilji war cruiser Anvil, which was longer than the Hammer.
In 18 BBY, a Grysk operative known as "Jixtus," who had allied himself with the Illumine's ruler, Generalirius Nakirre, dispatched the general's task force to the Unknown Regions' Rapacc system. Seeking to retrieve a group of refugees hiding on the planet Rapacc, the Kilji force arrived at Rapacc and was confronted by the Paccosh-commandeered Nikardun blockade frigate Aelos. Crofyp prepared a cross-fire attack on the Aelos after its commander, Uingali foar Marocsaa, refused to allow the Kiljis to retrieve the refugees; however, the Chiss heavy cruiser Springhawk—whose crew gave the Hammer the name of "Cruiser Two"—disabled the Anvil, destroying the war cruiser while the Hammer fled to the Unknown Regions' "Sunrise" system.
There, the Kilji vessel kept station with a Grysk vessel. However, the Aelos tracked down the Hammer, and the blockade frigate's crew boarded the picket cruiser. They stole data on the Illumine's battle fleet, the Illumine Kilhorde, and commandeered the cruiser, using it to attack the Grysk vessel while the Springhawk—whose crew codenamed the Hammer as "Bogey Two"—arrived. The Grysk warship destroyed the Hammer and escaped into hyperspace.
A Kilji picket cruiser, the Hammer was armed with spectrum lasers. It was equipped with a main drive, a hyperdrive, and a tractor beam. The picket cruiser's hull featured weapon clusters that housed the starship's tractor beam projector and a docking port that led to a vestibule. The Hammers bridge featured a helm, a weapons station, and the pilot's chair. Two stations located to starboard and portside respectively controlled the spectrum lasers. The stations' controls were laid out with extreme simplicity. Sister ship to the Kilji war cruisers Anvil and Whetstone, the Hammer was designed around a first-strike strategy.
The Hammer was commanded by Tildnis, a colonel in the Kilji species' nation, the Kilji Illumine. The picket cruiser and the Anvil formed Illumine General Crofyp's task force. In 18 BBY, "Jixtus," a Grysk operative who had allied himself with the ruler of the Illumine, Generalirius Nakirre, dispatched Crofyp's task force to the Unknown Regions' Rapacc system. The Grysk tasked Crofyp's forces with capturing a group of refugees that had taken refuge on the star system's planet Rapacc, assigning two Pathfinder navigators, Sarsh and Qilori, to the Hammer and the Anvil respectively. While the two vessels traveled to the Rapacc system, the Hammer slowed down, prompting Qilori to stop the Anvils journey through hyperspace so that the shorter picket cruiser could catch up. Once Tildnis's cruiser arrived near Crofyp's flagship, the two vessels resumed their journey and arrived at Rapacc simultaneously.
The Chiss heavy cruiser (one such starship pictured) Springhawk engaged the Hammer and the Anvil at Rapacc.
The Paccosh-commandeered Nikardun blockade frigate Aelos confronted the Kiljis. Commander Uingali foar Marocsaa, the blockade frigate's commander, refused to allow the Kilji force to retrieve the refugees after Crofyp instructed him to move aside, prompting the general to move his warships for a cross fire attack on the Aelos. The Hammer moved past the Aelos along its portside and the Anvil did likewise along the frigate's starboard.
Once the Kilji vessels were in position, the Chiss heavy cruiser Springhawk—commanded by Senior Captain Mitth'raw'nuruodo, core name "Thrawn" and whose crew codenamed the Hammer as "Cruiser Two"—arrived and disabled the Anvil with vessel-disabling plasma sphere weapons. Under Crofyp's directive, the Hammer and the Anvil fired spectrum laser volleys at the Springhawk before the heavy cruiser destroyed the Kilji flagship while it shielded Tildnis's cruiser. The Hammer fled to an Unknown Regions system known as the "Sunrise" system. Thrawn rescued Qilori, who escaped the Anvils destruction by using an escape pod, and commanded him to use the Force to track down Sarsh and the Hammer.
Senior Captain Mitth'raw'nuruodo and his allies boarded the Kilji picket cruiser Hammer.
After it arrived at Sunrise, the Hammer kept station with one of Jixtus's Grysk vessels over a planet known as "Sunrise." Hours after the picket cruiser fled to the Sunrise system, Qilori located the vessel and brought the Aelos to the Kilji warship's location. Marocsaa asked the Hammer for protection and a safe haven while his crew repaired his frigate, claiming that the Chiss were pursuing him. The Grysk vessel's commander agreed to provide a haven to the Paccosh, directing them to the Hammers portside. The Kiljis attempted to move the Aelos below the picket cruiser's weapons cluster; however, the Paccosh vessel disabled the tractor beam, which was moving the blockade frigate, with a Crippler net weapon, boarding the Kilji cruiser.
As a team of Paccian commandos killed all the Kiljis aboard, including Tildnis, the Springhawk, whose crew gave the Hammer the name "Bogey Two," arrived. The Chiss cruiser attacked the Grysk vessel while the boarders made their way to the Kilji picket cruiser's bridge. On the bridge, Thrawn and Qilori coerced Sarsh into stealing a Kilji data rectangle containing data on the Illumine's battle fleet, the Illumine Kilhorde. The Paccosh soldiers commandeered the Hammers weapons stations and began an attack on the Grysk warship, destroying the Grysk dibber missiles that were protecting several larger missiles that the Grysks had fired at the Springhawk. The Chiss cruiser subsequently destroyed the other missiles, attacking the Grysk war vessel; however, after the Aeloss crew left the Hammer, the Grysks destroyed the picket cruiser and escaped into hyperspace. Shortly after, Qilori told Jixtus how the Chiss and the Paccosh had destroyed Crofyp's task force.
Thrawn shared the data on the Kilhorde with the Paataatus Hiveborn, the nation of the Paataatus species. The Hiveborn used the data to obliterate the Kilji fleet. The senior captain later told Nakirre that the Paataatus used the data Thrawn and his allies had retrieved from the Hammer to destroy the Kilhorde.
The Hammers crew included Colonel Tildnis, the vessel's captain, and twelve Kiljis.
The Hammer appeared in the 2021 novel Thrawn Ascendancy: Lesser Evil, the final volume in the Star Wars: The Ascendancy Trilogy written by Timothy Zahn.