Pan-Solar Empire
The Pan-Solar Empire is a totalitarian autocracy spanning nearly 25,000 worlds. It is the stated philosophy of the Empire to serve the Emperor and the military/corporate government, in other words, make a profit. To this end, the individual Imperial citizen has no rights and is considered the property of the state.
This unequal economic and social arrangement has resulted in a very statified upper echelon of military and corporate overlords while the vast majority of Imperial citizens live in abject squalor and oppression. Natural resources are pillaged from worlds to fuel the unchecked military and economic growth of the Empire.
The Empire maintains a vast military force to maintain opression at home and to acquire new resources to maintain the massive growth.
The Empire views the Federation's wealth and prosperity with menacingly hungry eyes. They would like nothing more than to topple the Federation and acquire its vast resources.
Current Federation military strength and deployment serves as an effective deterrent to any such Imperial attack, but minor raids still occur on the outlying Frontier worlds.