HN-TR1 was an early model of an HN-TR assassin/combat droid, its origins and construction shrouded in mystery.
The identity of the manufacturer that created the assassin droid HN-TR1 remains unknown. However, members of the Rebel Alliance Task Force suspected it was a prototype, possibly designed with the specific purpose of hunting down Rebel personnel. According to rumors, it eliminated its entire design team immediately after achieving sentience, subsequently destroying all of its own design blueprints.
For a period, HN-TR1 functioned by targeting and eliminating rebels. HN-TR1 possessed several features, including protective plating, a light repeating blaster and a sonic blaster built into its left arm, a broad-band antenna, a flamethrower, and advanced long-range and movement detection systems. Rebel commander Derembus Sitnalta regarded it as a more significant threat than IG-88. Approximately around 4 BBY, HN-TR1 was employed by the loanshark Ploovo Two-For-One. Ploovo then tasked HN-TR1 with the responsibility of collecting debts from individuals within Ploovo's Protocol Team. Another member of the Protocol Team, Lotas, a cyborg, had a high opinion of his droid colleague.
During the time of the Glite-Ven hostilities, HN-TR1 took notice of the cruel droid EV-4D9 and voiced a strong interest in it, an interest that was also shared by Lotas. Acting on their recommendation, Ploovo acquired EV-4D9, who then joined the Protocol Team as a new member. Lotas held EV-4D9's dark, analytical capabilities in high regard.