The Cluster is the star system that is the setting for the first season of Shadow Riders.
At an unkown point in time the cluster planets were visited by an unkown antient race that installed World engines at the core of each planet. These engine systems were known to the Beast Planet's forces who were determined to wipe out any planet that had them.
Long before encountering the Beast Planet the planets of Ice, Rock, Bone and Fire had been in constant war. Each planet contained an element nessasary for the other's survival. Elements that only exist in small quanties on their own worlds.
After numerous attempts at peace failed the four worlds resorted to raiding each other for these elements; locking the system in constant war till the threat of the Beast Planet. Putting aside all hostilities to one another for the survival of their civilizations, the world engines were discovered and used to leave their home system to avoid any chance of the Beast planet from 'devouring' them.
Ramora: The furthest planet from the Cluster's star was a dead empty world that never produced life. It was used by the Beast Planet's forces as a base of operation.
Ice: The second furthest from the from the planet's star. The world is covered in arctic wastes and raides by its neighbours for its frozen water. The natives of the planet resemble bipedal insects and are masters of nano technolegy.
Rock: The third planet in the Cluster, raided by its neighbours for its abundance of ore and minerals. The world is covered in large mountains and surrounded by five artificial moons theat have been weaponised by the natives. The people of Rock are similar in appearance to humans but covered in rock like skin. They specialise in industry.
Bone: The fourth planet in the system and raided for its bio matter. Bone is covered in thick marsh lands and swamps. The planet gets its name from the masive skeletal remains of prehistoric creatures that once roamed the planet. The natives are humanoid reptiles and the planet specialises in agriculture.
Fire: The fourth planet and the closest to the cluster star; Fire was a volcanic world raided for energy by its neighbours. The natives are a mix of humanoid and insectoid beings with volcanic like bodies. The planet specialises in energy based weapons. The fire planet was destroyed after the failed attempt to use the engines to destroy the Beast Planet.