I get that Dimitri is crazy and they want to force you to fight both armies, and they even do that bit with the empire killing the messenger to make you think that the Golden Deer are not on your side, but the way it plays out in battle is dumb. I started moving all my units towards Edelgard, not wanting to attack the Alliance troops, but then Dimitri launches a surprise attack for seemingly no reason. What they *should* have done is made this a fog of war map. I thought that's what they were going to do, given that we hadn't really had any major fog of war maps since that one paralogue with Rhea, and at the beginning of that fight Edelgard has her fire troops drop fire to cause confusion. If they had made it Fog of War, then it would have made more sense if Alliance soldiers started attacking you out of the fog and you had to kill them. Would have sold the tragedy of that event way more. But nope, it's just random storytelling.