The HK-87 assassin droid represents a specific assassin droid design. Throughout the eras of the Galactic Empire and the subsequent New Republic period, these droids functioned as both bodyguards and enforcers. In her governance over the city of Calodan located on the forest planet Corvus, Magistrate Morgan Elsbeth commanded a pair of these droids as part of her army. When the former Jedi, Ahsoka Tano, joined forces with the Mandalorian, Din Djarin, in an effort to defeat Elsbeth, the magistrate dispatched the two droids to aid in the pursuit of the attackers. Tano successfully destroyed one of the droids, while Djarin eliminated the other after Elsbeth's defeat, thus liberating the citizens of Calodan.
The HK-87 assassin droid, a type of assassin droid, was built using an older blueprint and had a humanoid shape. These droids featured body armor in an array of colors, with the exact color scheme differing between individual HK-87 units. Some droids exhibited a lighter shade on their torso paired with red limbs. Their heads presented a curved design that narrowed towards the rear, and their faces were composed of various ridges and tubes. The HK-87 assassin droid possessed enough agility to jump from the ground to the edge of a rooftop, and then perform a flip to pull itself up. These droids communicated using a deep-toned alien language.
Magistrate Morgan Elsbeth's HK-87 assassin droids were armed with blasters and wore cloaks draped across one side of their bodies. The chimaera symbol used by the Galactic Empire's Seventh Fleet was prominently displayed on the sides of the droids' heads.
Near the entrance of Magistrate Morgan Elsbeth's residence in Calodan, situated on the forest planet of Corvus, two HK-87 assassin droids were stationed. They were tasked with holding back the disgruntled residents who voiced their disapproval of the Nightsister of the Empire, claiming they only sought the planet's resources and did not provide jobs. Additionally, two more droids stood beside Elsbeth on a balcony when she perceived that the citizens lacked gratitude, despite her assurances that the Empire would assist them. Eventually, a small intruder managed to infiltrate the premises and engage Elsbeth in combat, defeating her mechanical guards. However, the Magistrate proved to be a formidable opponent, fighting on equal terms until Captain Gilad Pellaeon intervened, ordering both combatants to cease fighting, as the encounter served as a test for Admiral Thrawn, his superior within the Imperial Navy.
At some point following the Empire's downfall, an HK-87 unit accompanied Elsbeth when New Republic Ambassador Nadura and her New Republic soldiers demanded Elsbeth's surrender. Elsbeth refused and instructed her guards to eliminate Nadura and her delegation. The HK-87 unit was subsequently shot down by one of Nadura's guards.
In 9 ABY, during the time following the fall of the Galactic Empire, two HK-87 assassin droids were in the service of Magistrate Morgan Elsbeth, whose forces controlled the city of Calodan on the forest planet Corvus. When the former Jedi Ahsoka Tano—who was attempting to overcome Elsbeth and learn the whereabouts of her master, Thrawn, by then a Grand Admiral—killed the guards positioned outside the city, Elsbeth instructed her assassin droids to bring forth a prisoner, threatening to execute him and the other citizens of Calodan.
Tano demanded Elsbeth's surrender and then left, giving the magistrate one day to comply. Elsbeth then ordered her droids to confine the prisoner, and the two droids escorted the man away. Later, when the Mandalorian Din Djarin arrived at Calodan in search of Tano, Elsbeth met with Djarin, accompanied by an HK-87 assassin droid that carried her beskar spear. Elsbeth had the droid present her with the weapon, offering it to Djarin as a reward for eliminating Tano.
However, Djarin did not intend to kill Tano, and the two chose to work together to defeat Elsbeth and liberate the citizens of Calodan. After Tano dealt with the guards at the city's entrance, Magistrate Elsbeth emerged from her quarters, escorted by her two HK-87 assassin droids. As Tano entered the city, the assassin droids aimed their blaster rifles at her, but Elsbeth ordered them to stand down. Claiming that she had defeated Djarin, Tano questioned Elsbeth about her master, prompting the magistrate to order her forces to eliminate the Jedi. Tano escaped, drawing away the guards, and Elsbeth sent her droids to accompany her hired gunfighter, Lang, in pursuit.
As Lang and the droids pursued Tano through the city, the former Jedi jumped down from above, disarming Lang. The two droids opened fire on Tano, but she used her lightsabers to deflect the shots. After destroying one of the assassin droids, Tano escaped, and Lang ordered the other to climb onto a rooftop to continue the pursuit. Tano managed to defeat Elsbeth in combat, while Djarin shot and killed Lang. The remaining HK-87 assassin droid aimed at Djarin from a rooftop, but Governor Wing warned the Mandalorian of its presence, and Djarin shot the droid before it could fire, causing its body to fall to the ground.
Following the Liberation of Calodan, HK droids remained in Morgan's service and were sent to Arcana in search of a star map that could lead to the location of Grand Admiral Thrawn. After a battle with Tano, the remaining droids self destructed, destroying the stronghold. Droids later accompanied the mercenary Shin Hati to Lothal and successfully steal the map from Sabine Wren. One HK-87 unit remained at the LothalNet comm tower E-272, where it attempted to attack Tano but failed. Later, Wren worked to extract information from the droid's head, as it had several built-in backup systems that allowed the droid's memory core to remain partially active even after termination. However, if the power levels were correct, the droid's memory could be recovered to find its origin, but if incorrect, it would self-destruct. One HK-87 droid had a high-level security clearance to prevent the protocol droid C1-D1 from completing her inventory duties. During the subsequent mission to Corellia, an HK unit fought alongside the Inquisitor Marrok during his duel with Tano, who destroyed the droid.
The HK-87 assassin droid made its debut in "Chapter 13: The Jedi," which was the fifth episode of the second season of The Mandalorian television series. It was released on Disney+ on November 27, 2020. The design of the HK-87 assassin droid shares similarities with concept art created by Ralph McQuarrie for a droid bounty hunter in Star Wars: Episode V The Empire Strikes Back.
Despite their visual differences, the droid model's name is reminiscent of the Jedi hunter droids known as the HK-series assassin droid from the Legends continuity, particularly unit HK-47. The HK series has a counterpart in the new Star Wars canon in the form of the HK-model of gladiator and assassin droid, a droid line of which the HK-87 is a model of. Canonically, the HK-87 is also noted to be inspired by an antiquated design, matching the HK-series's usage as far back as the Old Republic era in Legends.