Eastern Empire Emergence

I've been reading a ton about the Eastern Roman Empire recently.  A fascinating period of triumphs and losses.  An interesting time period to consider as inspiration for settings.  I'm imagining a powerful but faraway empire teetering between decline and territorial gains.  Largely concerned with fighting off distant enemies on the other side of the globe, and able to influence events in the campaign setting but not control them. We could picture them like the New California Republic in Fallout: New Vegas.

Also, interesting power dynamics are possible.  Oftentimes the ERE would go to war or launch raids against territories that were nominally theirs, or at least owed them fealty.

So to start introducing this idea, we can use a bog-standard traditional fantasy world, with kings, dukes, etc.  An expeditionary force from the Eastern Empire marches across the plains, their arms and armor of strange make, their customs and appearance alien. Their general Theodoric the Orc calls on various kings and dukes to remind them of oaths of fealty and suzerainty made years ago.  The kings are not happy to be reminded.

The force was meant to march west, receive the barbarous forces of their allies and subjects, and march northeast to open a new front in the ongoing war between the Empire and the Enemy.  However, the various dukes and kings are finding reasons to delay their entry into a costly foreign war. The glittering troops of the Empire have bogged down in a camp outside the capital, and as delays continue tensions are mounting. The army was meant to receive part of their pay as plunder, and the bored, underpaid soldiers are starting to eye the wealth and resources of the area. The kings are starting to wonder if this glittering Empire they've never seen ought to ruling over them.

The Empire's Camp

Located outside the Capital, this hastily arranged war camp was meant to be a temporary stop, but has developed into a small fortified compound as Empire engineers have plied their trade over several weeks. High earthen walls and spiked pits around the edge. Theodoric the Orc holds court in an elaborate tent in the middle.  He is an actual orc, adopted by a leading Empire family. He is steeped in Empire culture and tradition, and has risen to this high command due to his fastidious nature and battlefield acumen. Fervently religious, he is a follower of the Lord of Dawn, which weirds out a lot of the locals. While he is angry at the recalcitrance of the local lords, he has recently learned of a possible cause. A bastard half-brother of the emperor, Flavius Aspar, fled here quietly 2 years ago and has taken refuge among the lords.  He stirs them to rebellion. Theodoric is looking for local adventurers to track and find Flavius Aspar and bring him to the Emperor's justice.