In about - 370 before the signing of the Treaty of Coruscant, the Czerka corporation had the idea of the assassin droid, the design of which would bypass the restrictions of several planets regarding this market. A droid that would even be able to infiltrate high circles to execute its targets without being spotted because of its heavy carcass. This is how the Hunter Killer series of droids, better known under the name HK, was born.
A project that began with a disaster. Prototype HK-01 fled and embarked on a crusade to free its droid brothers from their masters. After reprogramming them, he launched them to assault any organic target within range. If the army he activated as part of what is called the Great Droid Revolution was spread throughout the Republican space, it is on the capital Coruscant that the bulk of the fighting was concentrated. HK-01 is eventually destroyed and dismantled by a group of Jedi including the famous Arca Jeth. Several weeks of Chaos, but the Czerka manages not to be worried. The failure didn't deter them, it just forced them to be more discreet to prevent such a situation from happening again.
The following units in the series will indeed be more discreet. They were not successful enough to be mass produced, but there was still one to fund the next version. This until number 24.
HK-24's success did not come from its performance, which was rather understated at the time. Lord Arkoh Adasca, president of the company Adascorp placed a large order. They are the ones who owned almost all of the production of this model. This Arkanian entrepreneur had great galactic ambitions, and arming himself with an army of incorruptible private agents had everything to render him great services.
Lord Adasca rose in the shadows, waiting for the moment when he could reveal himself and take the chance. When he chose to do so, it was without taking into account certain parameters and misjudging his situation. At the start of the Mandalorian Wars, he invited the different camps to his flagship The Arkanian Legacy for an auction of certain weapons. His claims fell flat. Malak the representative of the Revanchists, Master Lucien Drayy of the Jedi Council and some soldiers of the Republic provoked the conflict to destroy these new weapons. Mandalore the Ultimate did not find the offer attractive enough to commit all of his forces to the Battle of Omonoth. The Arkanian Legacy was destroyed, with his ship in command of these new weapons, Lord Adasca and his entire stockpile of HK-24 units.
What could Czerka retain from this element of her series? A relative success, due to one man. Or rather a single Arkanian. If one had to rely on a single customer each time to sell all copies, that would not be viable. New poles of attractiveness had to be found in order to sell new copies. But on the other hand, HK-24 had been fully operational and efficient. The changes to be made would only be improvements.
A few years later, in the midst of the Mandalorian Wars, the Revanchist-turned-Revan received a HK-47 unit as a gift. He no longer received a utility droid but a true protocol droid capable of holding both of his programming. Many consider this unit to be the climax of the series.
It may seem ironic that a Jedi Master is using an Assassin Droid. And yet, his HK-47 unit was among his confirmed regular companions. Revan was decidedly no ordinary Jedi. He will add several programs and improvements to his droid, but will never touch his independence and his thirst for blood. This reinforcement of its effectiveness will contribute to its success and one will find as much among the leaders of the Hutt cartel as in the corridors of the Senate of Coruscant ...
HK-47 will disappear from Revan's entourage before the end of the Mandalorian Wars, and none are listed after he became a Sith lord and a traitor to the Republic. Moreover, the model was now fairly well known and lost the discretion and concealment effect that the series was supposed to have. Sales eroded, and sales of Units 48 and 49 were so bad that the Hunter Killers seemed to reach their last chance.
But a sponsor passed by. His identity remains unknown, although several intelligence agencies would like to get their hands on it. There are rumors of crime lord Goto, but there is nothing confirmed. A new generation of HK droids was designed, for the personal use of this sponsor, the HK-50.
It is not known what the plan of this sponsor was. The effects were felt, identified, but the general plan has never been identified. Several HK-50 units had to face a group of Jedi, including several apprentices and an old HK-47. Following these fights, the Republic was alerted to the presence of HK-50 units on many points of trouble, including the decks of its own ships, and began to clean up. With the droids functioning in small, independent units, studying their memories yielded only a few random pieces of a giant puzzle.
The extent of the conflicts triggered by the actions of the HK-50s is still difficult to assess. Some weakened the Republic, but others favored it. When the news spread, the HK-50 units were dismantled.
Three hundred years later, the Czerka no longer produced a new HK unit. There have been rumors of Models 51 and 52 for the sponsor of 50 Units, but none have been offered for sale. There is no trace of their existence.
And yet, when the Empire attacked Corellia, droids strangely resembling HK units were spotted on the streets of Coronet City, preying on Republican forces. And then there are those recently discovered leaflets where the Czerka touted HK-51 units to change the course of the last war. But they stopped after the transporter containing them disappeared into the Middle Rim ...