Yeah, somebody could explain better the reason of the war, who is in it and in which country is the blue carp town. It's badly explained in the story, because 1) it's always a few small cases with mainly texts explaining the whole situation
2) there is a lot of things happening (it's not just "country A attack country B")
3) the names are confusing for westerners (it's either chinese names heard for the first time (not introduced before in the story) or names too general (imperial army, divine guards, dragon guards, and whatnot. You could replace guards with palace and you would have a chinese restaurant)