The 9D9-s54 Dianoga spy droid represented a type of spy droid that the Imperial Department of Military Research engineered explicitly for espionage missions. Endowed with intelligence, these droids possessed a seemingly basic construction while incorporating tracking and identification systems. These systems enabled them to monitor subjects and capture their actions with a high-resolution holorecorder. Subsequently, the droids would relay this information through protected communications lines to the Galactic Empire. An agent of the Imperial Security Bureau, specifically Kallus, deployed a spy droid to monitor the activities of Minister Maketh Tua. Furthermore, the droid documented her assassination, with the intention of falsely accusing the rebels from Lothal of perpetrating her murder.