So I took a stab at outlining the Zakar Imperium. I imagine it as having a kind of Byzantineness to it, as far as aesthetics. Any comments or suggestions would be appreciated.
History: Ahmad Al-Zakar was a shrewd and cunning Lebanese general during World War II. One night his men captured a crashed UFO (one of the Arbiter's ships) that had been damaged and the crew killed when it flew too close to a battle between German and British forces. Whilst aboard with a few of his men that were examining the strange 'flying disc' the craft inadvertently took flight and transported Al-Zakar seemingly back in time to what appeared to be the 2nd century, but which was really an alternate earth. Unable to properly operate the craft to return home, Al-Zakar saw a chance at glory and took it. Using a replicator device aboard the fantastically advanced Arbiter ship to create many copies of the machine guns he and his men had with them, he allied with a Parthian prince and trained a few thousand Assyrians to use these firearms, and then marched on Rome. He easily captured the city, effectively seizing control of the Roman Empire. Al-Zakar turned it into the Zakar Imperium and went on to conquer the Parthian Empire and Han China. Centuries later, after studying the technology of the Arbiter ship, the Zakar Imperium that now controlled all of earth were able to construct other crude but functioning vessels, which they used to carry out a policy of aggressive imperial expansion. By the second millennium the Zakar Imperium had conquered thousands of alternate realities and realms across the multiverse, applying the Ancient Roman bureaucratic approach to conquest that ran things much like a huge business enterprise.
Significant ideologies: The goal of the Zakar was to accumulate fabulous wealth and establish a multiversial domain that, much like the multiverse itself, would have no apparent end. They financed their military invasions through the slave trade that provided a ceaseless supply of disposable labour and slave soldiers. Due to their rapidly continuing expansion, their control over their territory was at first relatively weak until they began to encounter rival powers such as the Hont, and the Draemorthan Union that insidiously rose from within the borders of the Imperium itself to overthrow the Zakar.
Significant Institutions: The Zakar are ruled over by an Emperor who is the head of the Zakar dynasty, the ruling family that trace their lineage to the Imperium's original founder. The Imperium is made up of numerous interdimensional sectors comprising hundreds of conquered worlds; the sectors are ruled over by a supreme imperial governor and each single world by a minor imperial governor. The governors command the Zakar military forces that are divided among them, including immense Legions and smaller Auxiliaries. More wealthier and powerful than many of these governors are the great Slaver Khans of Zakar, who command a monopoly on the fierce and lucrative slave trade. The rich clans of Slaver Khans have their own private armies of soldiers and raiders, and collectively they keep the marketplaces across the Imperium flooded with human and humanoid trade goods, which are in such high economic demand that entire world populations have been known to sometimes be sold into slavery.
Major Technologies: Interdimensinal capable ships that are crude, inferior versions of the Arbiters vessels. Directed energy weapons of various types. Missiles. Energy shields. Unlimited and cheap cold fusion power. Anti-gravity devices. Cybernetic enhanced soldiers. Nanites that can be used to medically heal organic tissue, or used as weapons to tear it apart.
Additional comments: After many centuries of continual and largely unchallenged expansion, the cruel and decadent Zakar are now struggling to hold off the powerful Hontian Empire, the upstart Draemorthan Union, and the unseen hand of the Followers of Chaos that sew internal dissent and feuds among the Zakar governors and khans.