Kilobots (known as Death Medarots in the Japanese version) are a type of Medabot that only appeared in Medabots Spirits. In the video games, there was no difference between Kilobots and regular Medabots.
Kilobots are shown to be much more powerful than standard Medabots since they use Ex Medals in place of standard ones. Also unlike regular Medabots the Medals meant for Kilobots have no personality, making them simply machines who will carry out any orders. The Medals also make them mostly immune to Medaforce-based attacks. The Medaforce attack from Metabee only inflicted 1% damage to the Kilobot he was fighting.
A Medafighter using a Kilobot, or a normal Medabot equipped with an Ex Medal, is refered to as a "Rogue Medafighter". This however is due more to Medafighter ignoring the rules of a robattle.