Like many things, when the UEE expanded not all cultures that were assimilated into the Empire did so willingly or with little struggle. The main one of these being the Lithosians, who at the time was also running for territory. Though peace negotiations with this caste race have been attempted, all have yet to bear fruit and resolve the matter.
The only thing to have been created to help lessen the amount of damage created by the two waring factions was the neutral zone. It is an expanse running between the edging systems of the UEE and the Lithosian high command. Under no circumstances should a UEE vessel cross into this zone.
Many of the Lithosian advanced guard who monitor this zone have been pulled back deeper into their space. UEE intelligence has gathered this is because the Lithosian government is going through a civil war of their own. As far as we can tell two warrior brothers are fighting for control of the system.
At this time the UEE security council has issued a warning to stay away from and do not approach the neutral zone.