HK-01 was a rogue Hunter-Killer assassin droid in operation around 4015 BBY. It was thought that, after gaining a degree of artificial intelligence, HK-01 instigated what became the Great Droid Revolution. Despite his impressive command of his new army, HK-01 was unable to remain in control of the droids, and his orders were soon deciphered and traced by agents of the Galactic Republic. The Jedi Knights were able to locate the source of these dangerous communications, and shut HK-01 down.