A Paataatus attack fleet belonged to the government of the Paataatus Hiveborn, a species originating from the Unknown Regions, known as the Paataatus. Following the retrieval of data pertaining to the Kilji species' combat fleet, the Illumine Kilhorde, including its vulnerabilities and strategic approaches, by Chiss Senior Captain Mitth'raw'nuruodo, whose core name was "Thrawn," from the Kilji picket cruiser Hammer in 18 BBY, the information was conveyed to the Hiveborn.
After observing the operations of the Kilhorde in close proximity to their territory, the government considered the fleet's actions intolerable. Consequently, they dispatched the attack fleet to confront the Kilji force, resulting in its annihilation. The demise of the Kilhorde rendered Generalirius Nakirre, the leader of the Kiljis, inconsequential to his Grysk confederate, "Jixtus," who killed the generalirius based on intelligence provided by Thrawn regarding the Paataatus' impending assault.
The 2021 novel Thrawn Ascendancy: Lesser Evil, which serves as the concluding installment of Timothy Zahn's Star Wars: The Ascendancy Trilogy, featured a reference to the Paataatus attack fleet.