Terror Troopers were an experimental class of elite stormtroopers by the Imperial Department of Military Research. Shortly after the Galactic Civil War began with the founding of the Alliance to Restore the Republic, Darth Vader dispatched several of these soldiers to assist the bounty hunter Boba Fett in the Galactic Empire mission to capture Juno Eclipse.
The Terror Troopers were created as cyborg experiments conducted by the Imperial Department of Military Research. Their masks resembled those worn by the long-deceased Separatist leader General Grievous from the Clone Wars.
