One thousand years ago, the original Sathars invaded Volturnus. In their attempts to wipe out the Eorna race, they were victorious. However, because of the efforts of the Psi-Knights, they failed to take the planet for their own. The Psi-Knights closed it off from the rest of the Sathar forces by creating the nebula. The surviving Sathars on Volturnus were isolated and abandoned.
The surviving Sathars were not soldiers. They were part of the special operation to develop soldiers to fight the Eorna and their psionic powers. They hoped to expand that research to create regular psionically talented armies to fight for them. After the Psi-Knight Rising, the remaining Sathars retreated into their hidden facility, continuing their orders, hoping to rejoin their brethren eventually.
Generations later, the descendants of the Sathars of Volturnus continue their original mission, building a secret army in hopes that the homeland Sathars will return and use their efforts to take the rest of the galaxy [for their masters]. The mission orders evolved into religious doctrine, and their scientific practices into a monastic order. These descendants are now the Order of the Mane’Sharas vas Yawal (named after the last original generation commander).
They have continued experimentation on the three primary races – the Karabanda (fast attack and stealth troops with and immunity to psionics); The Ul-Mor (heavy weapons and mecha pilots with strong psionic abilities); and the Edekesti (general ground troops and labor slaves). They have thoroughly manipulated the Edekesti to extend their doctrine into the rest of the races in order to further their research. Using various rituals and ceremonies, they hope to weed out the strongest of both and build the army promised to the home world.