A Hunter-Killer assassin droid acted as both the personal property and a protocol droid for the Sith Lord known as Darth Scabrous. It was stationed at the Sith academy located on the Outer Rim planet called Odacer-Faustin. During the Cold War of 3645 BBY, which was fought between the Galactic Republic and the Sith Empire, the HK droid received orders from its master to accompany the Bounty hunter Dranok and his associate, Skarl, to the tower belonging to Scabrous. Later that same night, the droid journeyed to the Sith academy's landing platform to instruct mechanic Pergus Frode to cease refueling the bounty hunters' ship, because they had met their end at the hands of Scabrous. Subsequently, the HK droid escorted the Whiphid named Tulkh along with his prisoner, Hestizo Trace, who was a member of the Jedi Agricultural Corps, to the laboratory of its master. After some time had passed, a viral outbreak erupted within the academy during one of Scabrous' experiments, and Scabrous commanded the HK to recapture Trace, who had managed to escape amidst the chaos.
While engaged in its search for the Jedi prisoner, the droid encountered Tulkh and decided to team up with the bounty hunter. The two of them engaged in combat against both Sith zombies and tauntauns that had been infected by the virus, as they traversed the Sith academy towards Tulkh's vessel, the Mirocaw. As the pair advanced toward the ship, they discovered Frode already onboard the Mirocaw. The small group then proceeded with a plan to rescue Trace from Scabrous. During their attempt to escape, the ship was targeted by the defense systems of Scabrous' tower. The HK droid exited the ship, successfully infiltrated the tower, and disabled its defenses, but it was ultimately destroyed when the ground-based defenses opened fire on the tower.
During the Cold War era, a period of tension between the re-emerging Sith Empire and the Galactic Republic, this particular Hunter-Killer assassin droid functioned as the dedicated property and protocol droid serving the Sith Lord known as Darth Scabrous. Scabrous had equipped the droid with a restraining bolt designed to suppress both its assassination programming and any memory of those functions. In the year 3645 BBY, on the snowy Outer Rim planet of Odacer-Faustin, the droid, acting under the direct orders of Scabrous, escorted two bounty hunters, identified as Dranok and Skarl, to its Master's tower. Their purpose was to receive the remaining portion of their payment for delivering to Scabrous the Murakami orchid, a force-sensitive plant essential to an ancient Sith formula for achieving immortality. Upon reaching the tower, the HK droid escorted Dranok alone, carrying the "orchid," to present it to Scabrous. Scabrous realized that the orchid was a fake and told Dranok that he had failed him but he would receive payment anyway. The droid then brought in a cart with a large silver tray on it.
Dranok opened the tray to find his partner's stewed, severed head. The Nelvaanian's mouth had been forced open to accommodate the ripe red jaquira fruit that had been placed between its jaws. Scabrous offered him a chance to live after his betrayal, if he ate every bit of the Nelvaanian's head. Dranok instead attacked Scabrous, who choked him to death using the Force. Later that night, the HK was traveling through the landing pad of the academy when the academy's mechanic Pergus Frode questioned it about the bounty hunters and if he should keep refueling their ship.
The HK droid responded that he should stop refueling the ship and that the bounty hunters would not be returning. The HK unit later met the Whiphid Tulkh who brought the real Murakami orchid and his Jedi prisoner Hestizo Trace, the orchid's keeper, at Scabrous' tower. After performing a retinal scan to verify the bounty hunter's identity, the droid escorted the pair to Scabrous' lab. Shortly after, Tulkh gave Scabrous the real orchid and its keeper and was paid by the unit as it escorted him out.
The HK was later commed by Scabrous and given orders to activate the academy's outer perimeter barriers, scan Scabrous' lab for the Jedi's DNA and pheromone samples and use whatever means necessary to capture her alive. Shortly after obtaining the samples and locating Trace, the HK droid commed Scabrous and informed him that it had located the Jedi and that she and the Whiphid bounty hunter were spotted working together in the northeast section of the academy. The unit then discovered a large outbreak of Sith zombies that was spreading and alerted Scabrous of them.
Scabrous then informed the droid that he was on his way to take care of the Jedi and ordered the HK to prepare his ship. Later, the HK ran into Tulkh in the academy's training chamber and the Whiphid alerted the droid of its assassination protocols and activated them through the removal of the droid's restraining bolt. The HK unit then used its forearm-mounted augmented laser arrays and leg-mounted flamethrower to fight off a horde of Sith zombies. After the assassin droid destroyed almost all of the zombies, the last one attempted to attack Tulkh, only to receive his spear through its mouth. After the battle the droid and Tulkh raced back to the Whiphid's ship, the Mirocaw.
As they were making their way back to Tulkh's ship, the pair took turns in eliminating the zombies. During the Whiphid's turn, he broke his spear when he decapitated one zombie. After that, he offered the head of the spear as a keepsake to the HK unit, who declined the gift. The HK droid then alerted Tulkh of a new incoming horde of zombie tauntauns. The HK used its flamethrower and laser arrays to take care of the first tauntaun. As a horde started entering the room the pair discovered that the zombies were riding inside of the beasts.
The assassin droid saved Tulkh as one of the beasts tried to infect the Whiphid with its infected bloody spit. As they started to become overwhelmed, the HK fired a mortar round into the center of the horde, destroying them. After the skirmish the pair continued to make their way to Tulkh's ship, however neither noticed that a tauntaun had managed to land a infected blob of spit on Tulkh's eyebrow. When they arrived at the Whiphid's ship, they discovered that someone had taken Dranok's ship and crashed it nearby, before stowing away on Tulkh's ship.
The droid and Tulkh continued toward the Whiphid's ship with the intention of disposing of the stowaway. They discovered that the stowaway was the academy's mechanic Frode and had him take them to Darth Drear's, the academy's founder, Sith Temple and proceeded to rescue Trace. After getting Trace aboard their ship, the HK produced a syringe from its breastplate and took a sample of Trace's blood to verify whether or not she was infected. The assassin then confirmed that she was clean, but someone else was infected. As they tried to make their way off the planet they came under fire by the academy's perimeter cannons. Tulkh left the group and chained himself to the airlock door after realizing he was infected.
Trace then asked the droid where Tulkh disappeared to as they came under fire. When the HK did not answer, she then asked if it could remotely disable the cannons, to which the assassin droid responded that it no longer had control over them. Trace then asked how they could stop the cannons to which the HK droid responded that it might be able to override the main control system inside Dramath's tower. Trace then ordered Frode to land and the HK unit departed the ship the moment they landed. The assassin droid was able to deactivate the tower's defenses, but it was destroyed when the tower was fired upon by the ground-based defenses and exploded.
The HK droid had yellow photoreceptors and gray plating. A typical speech pattern for Hunter-Killer models was displayed by the droid: each statement began with a speech conditional that described its type. Uniquely, after its restraining bolt was removed, the droid dropped the speech conditional. While very formal if the restraining bolt was attached, the HK unit did not like being polite upon the bolt's removal. The HK unit took pleasure in killing and hated the Sith for enslaving it. The HK droid was able to produce light from its dorsal processor array. The assassin droid was also proficient in combat, as is normal for HK units.
The HK droid was armed with forearm-mounted augmented laser arrays, and its left leg was mounted with a flamethrower. The droid was also armed with mortar rounds. The HK unit was also equipped with a syringe and was able to take and process samples and with sensors that were able to scan and detect intruders and infections.
The HK droid first appeared in Joe Schreiber's novel Red Harvest, which was released on December 28, 2010. It was later pictured by Jeffery Carlisle and Chris Scalf in Pablo Hidalgo's reference book The Essential Reader's Companion, released on October 2, 2012.
While its description in the book notes it as having a grey/chromium chassis, artwork of this HK droid have it painted a bronze-like color.