The planet Alpha Prime was once ruled by the Mariedians, an advanced race of peaceful aliens who had created machines known as Robota to serve them. A scientist grieving for his lost child locked the child's soul within a Robota, thereby creating the first Soulborg. Many Soulborgs were then created, but eventually they rose up against the normal still living Mariedians and enslaved many of them, imprisoning them on the prison moon of Isadora. However some Mariedians escaped this fate and wage guerilla war against the Soulborg from their strongholds hidden deep underground.
The Soulborg are split into three main factions that war against each other, and while this war consumes most of their time and resources, the largest and most powerful faction are the evil Zettians who mercilessly hunt down the Mariedians that remain on Alpha Prime so that they may take them to Isadora, where they will be forced to work for the Zettian faction, which seems to to currently control Isadora.
To facilitate finding the organic rebels in their underground lairs, small rat-like Soulborgs were created, with advanced senses of smell, hearing, and sight. Their small size and agility enables them to easily crawl into tunnels and burrow through soft earth. As their main role is scouting and spying, they are not well-equipped for combat, although they are fitted with fairly strong armor. This is so that in case they are attacked by the rebels, they can them survive long enough to get away and return to the Soulborg command posts with the information they have discovered. The armor is as strong as their small frame allows, keeping in mind as well the necessity for speed and agility. Thus, it is nowhere near as strong as that of the Zettian Guards, but still very sturdy. Also in line with their roles as gatherers of information with which they must return safely, their programmed response when fired upon is to scatter in all directions and flee, distracting the attackers and making it difficult for them to get a clear shot at the scurrying rodent-like Soulborgs.
Although built by Soulborgs using the same technology, it is unknown if Deathreavers are actually sentient machines themselves. They may be only clever computer programming or if the life force of rodents were used in place of the soul of a Mariedian.