"The Eternal Empire of Zakuul doesn't have a population of loyal citizens large enough to fully crew its thousands of warships, much less its gargantuan Star Fortress battle stations. The solution: "EPHEMERIS" droids, advanced multi-tasking machines capable of running every vital system in an operational Star Fortress--and also provide defensive countermeasures should the organic command staff become incapacitated.
Though often mistaken for fully-functional artificial intelligences, EPHEMERIS droids are incapable of independence. These hybrid machines merely combine all the best features of Class 1 mathematics droids, Class 3 administration droids, and Class 4 assassin droids into a lethal and efficient package. Destroying an EPHEMERIS droid will not disable a Star Fortress, but the resulting system failures will greatly reduce the battle station's threat to the planet it orbits."