RogueTraderEnthusiast: The problem with a Danube supply route for the Germans is that once they get to the delta, they’re on the Black Sea. A brown-water fleet would be useless against Constantinople itself (the Andreas Niketas itself has more firepower than the entirety of the Roman Danube fleet). So they’d have to build a blue-water fleet literally in the backyard of the Roman Imperial Navy, all while said navy hurls everything it has at the construction sites.
Thats fair, but the Germans don't NEED to leave the Danube. Having a secure supply depot in Prusa means they have a quick way of supplying any campaigns near Constantinople, even if they can't apply naval power to the city itself.
Also, yay. Battle of Belgrade. I'm excited to see how it goes!