How a Realist Hero Rebuilt the Kingdom (Light Novel) Vol. 4Paperback, 17 September 2019

ALL'S FAIR IN LOVE AND WAR When the Principality of Amidonia sends a desperate call for help defending itself against civil war and enemy invasion, Souma agrees to aid their former enemy. But the Principality's plea comes with strings, or perhaps rewards, attached--including a marriage proposal from their princess!