The Hunter-Killer probot, also known as the H-K probot, represented a peculiar advancement from the more ubiquitous Viper probe droid. These units, manufactured by Arakyd Laboratories, were frequently deployed as independent patrol units in proximity to Imperial controlled planets.
Bearing a general resemblance to its predecessor, the Hunter-Killer was a technological behemoth scaled up to the size of a capital ship. The internal structure of each droid was specifically engineered as a holding facility for captured starships, with tractor beam emitters lining the external hull, prepared to pull errant vessels into one of several internal docking bays.
Once captured, detainees would be confined within the droid until the commanding Imperial officer received notification of the capture and decided on the appropriate action. They often operated in conjunction with Imperial Customs Frigates and Guardian-class patrol ships.
However, similar to capital-ships, a structural weakness existed: An imprisoned individual could potentially gain entry and seize control of a Hunter-Killer probot via its control center, thus creating the possibility of it turning against the Empire.
Following the success of the Viper probe droids in locating Rebel installations, Arakyd took a calculated risk by producing a massive 150-meter droid. The H-K gained substantial favor within the Empire, being utilized to capture smugglers and Rebel vessels.
Post-Palpatine's resurgence, a number of Hunter-Killers were stationed around Byss. A significant vulnerability in the design was exploited when Shug Ninx and Salla Zend, both smugglers, were apprehended by the HK probot Judgement 12-X7 while assisting New Republic operatives in infiltrating Byss. While piloting the Millennium Falcon to avoid Imperial detection, Shug and Salla were detained within Judgement 12-X7, but they managed to rewire the droid, seizing control of its circuitry and employing it to liberate Han Solo, Chewbacca, and Leia Organa Solo from an Imperial detention facility. However, during their escape attempt, an Imperial patrol detected the fleeing Republic prisoners, prompting Shug to redirect the probot's offensive systems against the patrol, resulting in an exchange of fire with the prison's security forces. As the Imperials engaged the rogue probot, Shug, Salla, Solo, Chewbacca, and Leia boarded the Millenium Falcon, which remained docked within Judgement 12-X7 alongside a Force projection of Luke Skywalker. Departing from within the reprogrammed probot, the Millenium Falcon and its crew successfully escaped Byss just as the prison's turbolasers found their mark and obliterated Judgement 12-X7.