The Katana fleet, also referenced as the Dark Force by certain reporters, comprised a vast armada of two hundred Dreadnaught-class heavy cruisers commissioned by the Galactic Republic during its twilight era, representing a significant element of the Galactic Senate's numerous ambitious endeavors. The fleet vanished during its inaugural voyage when a hive virus induced madness in its crews, leading the captain to initiate uncontrolled jumps into hyperspace.
Five years following the Battle of Endor, Grand Admiral Thrawn successfully persuaded the smuggler Captain Hoffner to reveal the whereabouts of the long-missing naval group. Upon discovering Thrawn's objective, the New Republic also began competing to locate the lost ships. Nevertheless, Thrawn's forces managed to abscond with 178 of the valuable vessels before the Republic's arrival.
During its final decades, the Senate of the Galactic Republic allocated substantial funding to numerous large-scale projects. One such project, finalized in 46 BBY, was the Katana fleet, a force of two hundred Dreadnaught-class heavy cruisers, each equipped with experimental AT-PT walkers. It was named in honor of its flagship, the Katana. To mitigate the significant personnel requirements of these ships, the fleet underwent extensive modifications incorporating full-rig slave circuitry, decreasing the necessary crew size to approximately 2,200 per vessel (down from over 16,000). To further set the Katana fleet apart, Rendili StarDrive redesigned the entire Dreadnaught interior specifically for this purpose, encompassing everything from the equipment and interior design to the dark gray hull finish. The fleet acquired the informal designation "the Dark Force," partly due to the hull's color and partly because the reduced crew size allowed for less interior lighting. With its cutting-edge slave-rig technology, the Katana fleet was poised to usher in a new era for military warships.
However, what was intended as a demonstration of efficiency devolved into a complete disaster. Aboard one or more of the ships, crew members contracted a hive virus at one of the ports of call during the fleet's initial mission. This virus, notable for inducing insanity in its victims shortly before their demise, spread throughout all two hundred Dreadnaughts while remaining dormant. When the virus suddenly activated, it incapacitated nearly everyone simultaneously. Rather than seeking assistance, the infected crew members linked their ships together, resulting in the Katana's command crew also succumbing to madness and initiating blind jumps into hyperspace, dragging the entire fleet along.
Following this fiasco, the Katana project became a source of embarrassment for the military authorities who had commissioned the fleet. While the incident did not initiate the movement toward decentralization in automated ship functions, it certainly solidified its outcome.
The incident garnered significant media attention, with some journalists employing sarcastic puns on the "Dark Force" name. For a few years, numerous eager salvage teams searched for the fleet, but without success. Locating a ship that had executed a random hyperspace jump was virtually impossible, and even two hundred ships could easily become lost within the vastness of space. By the time of the Clone Wars, the Republic's Senate Bureau of Intelligence concluded that Zeta Magnus, a genetic terrorist associated with the Confederacy of Independent Systems and a product of a freak experiment by the techno-lords of the Arkanian Dominion, was the mastermind behind the hive virus. The fleet eventually faded into legend, with some doubting its very existence.
The missing fleet remained lost until smuggler Captain Hoffner and his vessel inadvertently stumbled upon it in 6 BBY. Hoffner and his navigator/sensor officer, Talon Karrde were the only ones aboard aware of the find, but neither realized the other person knew the secret. They each concealed the fleet's location until the right time to make use of it. Hoffner later orchestrated the sale of individual Katana Dreadnaughts to Garm Bel Iblis, who eventually amassed a strike force of six of these ships, including his flagship, the Peregrine.
By 6 ABY, the balance of power among the New Republic, the Galactic Empire, and various warlord factions was so precarious that it was believed that whichever faction recovered the fleet would immediately become the dominant power in the galaxy, despite the fleet's age. The immense potential value of the Katana fleet was exploited to lure the Imperial II-class Star Destroyer Eviscerator away as a prelude to the Second Battle of Borleias.
In 9 ABY, almost fifty-five years after the fleet's disappearance, Grand Admiral Thrawn developed an interest in acquiring the fleet. However, the Grand Admiral's actions turned Mara Jade against the Galactic Empire, leading her, along with Luke Skywalker, to rescue Karrde from Thrawn's grasp and deliver the smuggler to the New Republic. Thrawn nonetheless succeeded in extracting the information from Hoffner, and while both sides secured portions of the fleet during the Battle for the Katana fleet, Thrawn had seized all but twenty-two of the Dreadnaughts before the New Republic forces arrived. These remaining vessels, excluding the one Dreadnaught destroyed during the battle, were integrated into the New Republic fleet, along with the AT-PT walkers later deployed in the campaign against Thrawn. Initially, the New Republic assumed Thrawn would be unable to effectively utilize his new ships, as he would require over three hundred thousand crew members for the Katana fleet—2,000 for each of the 178 vessels. However, Thrawn proved more resourceful, employing clones rapidly produced from Spaarti cloning cylinders within the Emperor's storehouse on Wayland to staff his ships. Luke Skywalker and Talon Karrde estimated that Thrawn's clones were 'grown' to maturity in fifteen to twenty days instead of the typical year to three years. Clones grown this quickly were generally known to be mentally unstable, but due to the use of Ysalamiri and their Force-neutralizing abilities, Thrawn's clones could be grown to perfection in a fraction of the typical time without this side effect.
Thrawn's acquisition of the Katana Dreadnaughts significantly enhanced his fleet's capabilities, enabling it to immediately launch attacks on more than twenty New Republic systems. In the later campaigns of Thrawn's fleet, it was a common vision to see a single Star Destroyer with several Dreadnoughts around, probably all from the Katana Fleet.
Talon Karrde indicated that the fleet was lost in 32 BBY (during the time of The Phantom Menace), while Captain Gilad Pellaeon placed the event fifty-five years prior to the story's timeline (which is set in 9 ABY.) The New Essential Chronology situates the fleet's launch after the Stark Hyperspace War, but does not explicitly state that it was lost in the same year, although the implication is that it was lost before 44 BBY. It is more probable that a high-ranking Imperial officer possesses the correct date than a smuggling chief, especially given Karrde's statement that it occurred "about ten years before the Clone Wars."
However, Jorus C'baoth was listed as having been killed on board the Outbound Flight in the computer archives of the flagship, Katana. Since the novel, Outbound Flight, lists the deployment of the Outbound Flight as being in between The Phantom Menace and Attack of the Clones in 27 BBY, this means the Katana fleet either was lost after the Outbound Flight, or that the information in the Katana's computer about C'baoth was automatically updated after the Katana fleet was lost.