HK-58 Aurek, an assassin droid of the HK-series, served HK-47 as he tried to conquer the world of Mustafar. A band of spacefarers ultimately destroyed it before proceeding to defeat HK-47.
Aurek, HK-58, possessed a link to its sibling, Besh; should either Aurek or Besh be defeated, the surviving droid would reactivate and resume combat unless destroyed within a five-second window. Similar to the smaller HK-77, both HK-58 Aurek and Besh were equipped with integrated disruptor weaponry in their arms.