The Imperial Leviathan were 5,000 meter-long starship-factories, precursors of the better-known World Devastators, which were able to produce several different kinds of vehicles and vessels.
The most sophisticated foundries and assembly lines of their time could be found on the inside of the vessels, their prime function being to recycle material taken in by the vessel. These systems, in an average hour, could produce either ten speeder bikes, five AT-ST's, three TIE/LN starfighters, or a single AT-AT.
The Leviathans were often used once the Empire had established itself on a new world. They would simply take in resources such as minerals, various metals, old or destroyed vehicles, or ruins of old constructions in order to build whatever was needed in a record amount of time. However, the ships had some disadvantages over the later World Devastators such as the fact that their weapon loadout had to be relatively low, and their compartments were often encumbered with a lot of transports and shuttles which were charged with collecting raw materials.
In addition, the use of so much automation and droids resulted in technological gaps, which New Republic spies were increasingly known for trying to exploit. A duo of well known droids even theorized that it should be possible to create a virus in the Leviathan's programming which would order their own self-destruction, although also estimated that the chances of leaving alive after successfully implanting the virus did not exceed 1 in 3,720.