Art Done by Blakmanta Of DeviantArt
They are a military faction and governing body much like Hitler and his Nazi Reich, comprising of robots. Although much less extreme and oppressive, the example still stands. The Cluster controls the planet of Cluster Prime , a planet completely inhabited by robots. The type of robots that make up most of the army are beetle like droids led by Smytus as their commander, and Vexus as their queen. Krakus is a known part of the Cluster, aiding them from time to time, although poorly with his inventions that fall apart or are easily destroyed.
The Cluster fell apart when Jenny came to Cluster Prime and helped liberate the people from Vexus’ hands. It is unkown what had happened to the rest of the army as every citizen on Cluster Prime has powers to match Jenny, with Vega saying, "We are no longer affiliated with those droids." It is known that Vexus, Smytus, and Krakus have been cooperating on waste asteroids, but the status of the Cluster as an entire is suspected to be complete and total destruction. There are some instances where the Cluster has used advanced androids and other types of robots in their attempts to seize Earth. In Escape from Cluster Prime, the Cluster began their invasion with very small attack bots that were invented by Krakus.
Their capabilities ranged from drilling into walls and tieing up humans. Also, they were not water proof, which proved to be problematic for the Cluster. When they fight against Jenny, their numbers do not serve then at any advantage. They occasionally find ways to trick her by using different types of force fields and other barriers, but they are quick to overcome and to be defeated. They have been known to run away on many occasions, not only from XJ9 but even from their own leaders. In "Sister Sledgehammer," it's shown that the Clusters can create a energy spider web and can assimilate.