Other Assassin Droids of the Same Model Series
HK-47 was a Hunter-Killer assassin droid and Jedi hunter constructed by the Dark Lord of the Sith, Darth Revan, shortly after the end of the Mandalorian Wars in 3960 BBY. HK-47 was sent throughout the galaxy on his missions and successfully assassinated countless targets whom Revan had deemed threats to galactic stability and peace.
The HK-50 series assassin droid was a HK series assassin/protocol droid model commissioned to be built by Revan, they were shut down for a long time due to his capture by the Jedi. Later, they were reactivated by G0-T0 who ordered them to bring all Jedi to him. The primary function of the HK-50 droids, as they stated it, was to "facilitate communications and terminate hostilities."
A series of droids, with the HK-51 designation, were made in the same Telos Military Manufacturing Facility as the HK-50 models. These droids were modified and commanded by HK-47 before being released into the galaxy. They assisted in the destruction of HK-50s and G0-T0. Answering solely to themselves and HK-47, most of them automatically deactivated when HK-47 was decommissioned.
Despite the ban on HK-series assassin droids by the Galactic Republic, the Czerka Corporation started to develop and manufacture several HK-51s on Nar Shaddaa in secret during the late stages of the Great Galactic War. This order was for the reconstituted Sith Empire, who intended to deploy the new droids around a decade into the Cold War. Czerka's HK-51 were programmed with faith-based subroutines dedicated to "the Maker" -- a powerful force similar to the Trandoshan "Scorekeeper."
HK-55 was a HK-series assassin droid that served the Sith Lord Lana Beniko during the conquest of the galaxy by the Eternal Empire and afterwards. He was programmed as a bodyguard, but also functioned as an assassin droid when required. After his destruction during the Battle of Asylum, he was eventually rebuilt and brought into the service of the Outlander.
HK-86, like ancestor HK-47, is unique. Originally an HK-51 unit from Telos, HK-86 renamed himself upon modifications to chassis, behavior core, and discovery that his designation had been usurped by Czerka Corporation. HK-86 is autonomous, self-repairing, and programmed for behavioral evolution. He is also classified as a class-3 droid since most of his processors are dedicated to communication protocols. "Language is mightier than the Lightsaber" being his mantra of efficiency in most disputes.
Unique and Evolving
Initially struggling with a sense of duality, from multiple behavior core frameworks being installed, HK-86 began a long process of modification. This included adapting, editing, and installing many protocols and data packets from various other droid models. He's now achieved a healthy desire to learn and adapt, and paranoid fear of a memory wipe, which he takes very seriously.
Starting with behavior core modifications, from HK-47 himself, HK-86 was given independence from droid subservience. As a result, HK-86 had to learn to look out for himself as well as his own reputation.
Assigning himself a unique designation of "86" -- as well as cosmetic alterations -- HK-86 has found many ways to make himself different from any other HK model (or droid, for that matter). 86 sees himself as a bridge between organic and cybernetic relations, aiding them to understand one another, as well as both groups understanding of his awesomeness. His penchant for violence is quite vital, still, but sees the 'art' in destroying a foe with no more than dialogue.