HK-series assassin droid

"Statement: I see you have purchased me, master. I find this a satisfactory arrangement. Am I to accompany you now? Shall I kill something for you?"

- HK-47 to Revan

The HK-series assassin droid, also known as the HK series protocol droid, was a series of combination of assassin droids and protocol droids. The series designation stands for "Hunter Killer," befitting their primary functions as assassins. They were originally manufactured by Czerka Corporation, then eventually by the Confederacy of Independent Systems. Their ability to perform the functions of a protocol droid became a major reason for their unmatched lethality, as they could and would often act as normal (if quite sinister looking) protocol droids, thus concealing their true function and allowing them to get closer to intended targets.

History
The first HK droid was Czerka Corporation's prototype HK-01. This progenitor of all HK-series droids was responsible for the Great Droid Revolution on Coruscant. He was destroyed by the Jedi Master Arca Jeth and the revolt was ended.

Seeing the effectiveness and potential of the HK series after witnessing the havoc HK-01 caused, the Czerka Corporation improved the design into the HK-24 series assassin droid. The HK-24 met little success on the market, as few had want of an assassin droid. Czerka halted production of the HK-24 and sold the entire remaining inventory to Arkoh Adasca, the head of Adascorp. Arkoh deployed the HK-24s to capture Gorman Vandrayk and as guards of various prisoners. The HK-24s were finally all destroyed during the First Battle of Omonoth while trying to protect their owner.

A unique, custom model, HK-47, was constructed by Revan shortly after the Mandalorian Wars using schematics of the HK-24. Despite looking more similar to the HK-01 prototype, HK-47 was much improved over the HK-24, and successfully assassinated several targets, including many Jedi. This was due to HK-47's extensive knowledge of how Jedi behaved and how to best counteract their Force abilities. Due to his large degree of autonomy and adaptive programming, HK-47 went on to become the longest surviving, most infamous, and most effective of the HK series.

Due to the effectiveness of HK-47, Revan also designed the HK-50 series assassin droid. With the HK-50s, Revan improved their armor and weapon proficiency, installing high yield explosives within their chassis, improving their self-maintenance capabilities and removing the static from their vocabulators. While the HK-50s were in many ways an improvement on HK-47, they were designed more for mass casualty infliction than their predecessor as they preferred killing as many targets with as little effort as possible. Originally designed to infiltrate and destroy Republic ships that would not defect to Revan's cause, Revan was defeated before he could deploy them. The HK-50s were instead deployed to capture any survivors of the First Jedi Purge after G0-T0 discovered them. Eventually, the HK-50s were destroyed by HK-47 after the latter infiltrated the HK's manufacturing facility, activated the prototype HK-51s, and turned them against the HK-50s. Sometime after, the Republic banned the ownership, manufacture, and use of HK series droids.

Close to the end of the Great Galactic War, Czerka Corporation manufactured several HK-51 droids at the behest of the Sith Empire. The HK-51s were designed for precision, specific assassinations, instead of mass casualties that the HK-50s preferred. Improving massively over their predecessors, HK-51s came preinstalled with a variety of weapons and abilities. Beyond a 21% improvement in blaster accuracy and thicker durasteel armor over the HK-50 model, HK-51s also came with micro-missile launchers instead of previous model's flamethrowers, a stealth field generator, greater mobility, and improved protocol functions. The HK-51s also had unique failsafes of their programming. The first caused the unit's assassination protocols to degrade, severely affecting their combat performance, until the HK-51 could no longer function at all, unless the HK-51 successfully assassinated a highly important figure in Republic Space. An exploitable flaw in this was that the subroutine did not specify who the target was loyal to. The second was a loyalty subroutine which would cause the HK-51 to be only loyal to a single owner and whoever that owner authorized. This was to prevent the HK-51 from being reprogrammed to assassinate their owner. One of the few, if only, shipments of HK-51s was stolen by the Dread Masters and was shot down onto the planet Belsavis where it sank into the ice. The crash caused almost all units onboard to be irreparably damaged and the ship was undiscovered until years after the war. After the ship's rediscovery, an unknown Spacer managed to repair and reactivate the sole salvageable HK-51 and had the droid serve as their personal assassin and bodyguard during their travels.

During the Galactic War, a small number of an unknown model HK droids (labeled "Imperial Shock Droids") were dispatched by the Sith Empire to help protect a captured smuggler's hanger on Corellia. Despite proving to be tougher combatants than any surrounding Imperial troops, these HK units were destroyed by a trooper from the Republic's Havoc Squad special forces unit.

Sometime after the appearance of the Eternal Empire, a droid called HK-55 was assigned to Lana Beniko as her bodyguard during her mission into Zakuul to free the Outlander. Unlike previous models HK-55 was designed and programmed as a bodyguard, instead of an assassin. His primary programming was to protect those in his charge against any and all threats, as well as assist them with daily operations. Thus his programming was closer to a steward droid that any previous model. After Lana freed the Outlander and their ship crashed, HK-55's sensors detected a massive unknown object with a large power source. He and the Outlander investigated, during which the Outlander inquired more about the droid. After locating the object and identifying it as the mythical "Gravestone" starship, HK-55 assisted with its repairs, as well as performing defensive patrols against hostile wildlife or Zakuul military forces. Once the repairs were complete, as well as fighting off the Zakuul forces that discovered them, HK-55 and the rest of the crew successfully managed to escape Zakuul onboard the Gravestone. After escaping into hyperspace (the trip being shortlived due to the Gravestone's hyperdrives being in a poor state of repair), the crew landed at the outlaw port of Asylum. HK-55 accompanied the Outlander on a few of his missions around the port, one of which wound up with a ion wall disabling him and erasing his memory of the past several hours. When Zakuul forces, lead by Emperor Arcann himself, attacked the port, HK-55 and Koth Vortena planted several explosive traps and ambushed teams of Zakuul forces while the Outlander worked to free the Gravestone from Asylum's gravity tethers. HK-55 was seemingly destroyed when he sacrificed himself to save the Outlander by throwing himself between the Outlander and a powerful force attack launched by Arcann. Due to wounds suffered in the battle, the Outlander was unable to recover HK-55's body. If asked if HK-55 had a back up, Lana Beniko responds that he specifically refused to have one made as he did not wish to live forever. SCORPIO quips that the HK-55 was an inferior droid, provoking a death threat from Lana Beniko. The Outlander states that HK-55 died as a true hero.

An unknown HK unit was owned by Sith Master Darth Scabrous. This HK was highly modified (able to withdraw and analyse blood samples with a built in syringe, as well as having several onboard weapon systems like a mortar cannon) and had gained full sentience. Due to this, Scabrous had a restraining bolt installed onto the HK to keep him subservient. During the "blackwing" virus outbreak at Scabrous's Sith Academy on Odacer-Faustin, the HK's restraining bolt was removed. He swiftly rebelled against his former master by assisting several of Scabrous's prisoners escape the Academy. To prevent his new-found allies' ship from being shot down by the Academy's defense cannons, the HK sacrificed itself by reprogramming the cannons to fire on Scabrous's tower (where the cannon's controls, and the HK itself, were located). A unique quirk with this HK unit was that, once its restraining bolt was removed, it ceased to preface its dialogue with the purpose of the sentence (i.e. Statement, Query, Thinly-Veiled Mockery, etc)

Eventually, the knowledge of the HK series became lost to time. This was until members of the Confederacy of Independent Systems discovered the wreck of a ship on Mustafar that contained the deactivated HK-47. Quickly realizing that HK-47 was superior than any droid they had ever seen (due to them activating HK-47 and the ancient droid proceeding to effortlessly slaughter several engineers and B2 Battle Droids), the engineers proceeded to build newer models that combine elements of HK-47's design with designs from their current battle droid models. They produced several prototypes including: HK-57s, HK-58 Aurek and HK-58 Besh, HK-67s, and the HK-Taskmaster, before settling with the HK-77s. These versions of the HKs were more similar to battle droids than their predecessors were, being meant for more frontline combat. They had blasters attached to the ends of their arms, hindering them from posing as protocol droids, and they were not as deadly or armored as their predecessors. Unfortunately for the Separatist engineers, Darth Vader arrived on the planet under the orders of the newly christened Emperor Palpatine and killed every member of the engineering team. HK-47, having had his data drive, behavior core, and personality core uploaded to the ship wreck before his body was taken by the engineering time; as well as the new HK battle droids, lay undiscovered for over 20 years. Upon rediscovery by a group of spacers, HK-47 managed to convince them to help him take control of the old droid factory. The group succeeded in their missions, only to be double crossed by HK-47. He used the droid factory to create a new body that was similar to his old one, installed himself into it. HK-47 then went on to gather all the old droids, including the various HK battle droids, to begin a war with all organic life. HK-47 ultimately failed as the spacers managed to destroy his factory, his army, and his body; but not before he managed to upload his consciousness to parts unknown.

Several HK-77 units were later recovered from Mustafar. Many of these units were reprogrammed and refitted as fire fighting droids via replacing their blasters with fire extinguishers and coating them in heat resistant chemicals. Another popular modification among the criminal underworld was to replace a HK-77's blasters with hands, increase their ability to calculate odds, and install data of gambling games, before using them as proxies for gambling events.

Known models

 * HK-01
 * HK-24
 * HK-47
 * HK-50
 * HK-51
 * Imperial Shock Droid
 * HK-55
 * Lord Scabrous's HK unit
 * HK-57
 * HK-58 Aurek
 * HK-58 Besh
 * HK-67
 * HK-77
 * HK-Taskmaster

HK protocol pacifist package
Sometime during the development of the HK-series, a module was developed that suppressed a HK's combat and assassination protocols. It appears to have been made to convert HKs into regular protocol droids, as opposed to their dual nature of assassin/protocol, probably in an attempt to better market the units.

Behind the scenes
The term HK "Hunter-Killer" was first used in Star Wars with HK-47, which in turn is a reference to the dropship of the same designation that appears in the BioWare game Shattered Steel, which in turn was a reference to BioWare writer Drew Karpyshyn's billiard team.

Appearances

 * Star Wars: Knights of the Old Republic 13: Days of Fear, Part 1
 * Star Wars: Knights of the Old Republic 14: Days of Fear, Part 2
 * Star Wars: Knights of the Old Republic 17: Nights of Anger, Part 2
 * Star Wars: Knights of the Old Republic: Daze of Hate
 * Star Wars: Knights of the Old Republic
 * Star Wars: Knights of the Old Republic II: The Sith Lords
 * Red Harvest
 * Star Wars: The Old Republic