The motto on Arnold's banners, Maior Natu, is (supposed to be at least) the Latin for "First Born". This is a reference to Arnold being the firstborn twin by a small margin, which makes his primary claim to the throne as eldest son.
The Margarethe and Franka Dragoon regiments are named after Prince Asgar's daughters. Thus, our aggressive Brigadier Murnau could find his career adversely affected were he to get them destroyed ingloriously. Glorious destruction is, of course, an entirely different matter. The dividing line between glorious and inglorious is, naturally, at the whims of Prince Asgar. :>
Note the presence of a Kinski Hussars in Asgar's forces, and a Brigadier Kinski in Arnold's forces. These two commanders are likely related. This is a common happening in civil wars.
Shannon's Irish Guards and the Von Trotta Horse Grenadiers from Asgar's force and the Schwarze Eber Fusiliers from Arnold's are all former Guards regiments under the deceased Landgrave.