Toaru Hikuushi e no Tsuioku, Nejimaki Seirei Senki: Tenkyou no Alderamin Recommendations
Both of the anime is about war between two nation. in "Nejimaki Seirei Senki", Katjvarna Empire and Kiorka Republic, while in "Toaru Hikuushi e no Tsuioku" Levamme Empire and the Amatsukami Imperium.
and both of the main character is a "HALF" between two nation.
if you like war story than you might like it :)