Before the invasion of Naboo, the trade federation and many of the other corporate entities in the galaxy were experiencing pirate attacks on almost all of their shipments from planet to planet. Because of this, they created an insane battle droid variant which served as an effective body guard in defensive mode, and a ruthless assassin in offensive mode. So, lets find out just how strong they were.
HKB-3 hunter killer battle droids were a group of easily modified droids that would serve as personal security and protection for Trade Federation shipments, as well as high ranking Federation officials. The droids had squared heads and were equipped with extremely powerful rapid-fire blasters, which could scorch through a significant amount of armor plating on the enemy. These droids were so effective, because they were all linked up to a central control computer, within the main separatist droid control system, which allowed them to coordinate their operations between each other. Each one of these droids had access to the location and visual data from every other one of the same model, meaning they literally had thousands of eyes across the battlefield, and even across different planets.
This made them so effective tracking targets because they could easily coordinate with each other and went out in small, assassin groups. Individually, each of these droids had pretty poor targeting abilities, but that wasn’t what they were designed for. They were designed to hunt in medium to large packs, where individual accuracy didn’t really matter, because the sheer amount fire from the group as a whole would be unavoidable. If one droid homed in on a target, he could immediately send that data to the ones around him, causing the entire patrol group to concentrate their fire on a single target. This made them incredibly effective pack hunters, and you would almost never see one of them roaming around alone.