The Gustaff is the Bonnes' lead battle robot, capable of handling intense combat and exploring all kinds of terrain and environments. This powerful machine can move fast, maneuver well, lift anything from trees to cars, and blow away its opponents with its arm cannon. Additionally, the Gustaff can receive numerous upgrades making it all the more formidable.

Teisel Bonne himself is originally shown as the pilot for Gustaff, however Tron is forced to take control after he is kidnapped. When Tron herself is also kidnapped it is up to the favorite Servbot to take over.

In addition to weapon and armor upgrades, the Gustaff can also receive a number of different paint jobs, and can equip tank treads in place of its legs making it useful for hauling heavy cargo.