High School Prodigies Have It Easy Even in Another World!, Vol. 9 (manga)

The high school prodigies have secured the Republic of Elm's place in the world by issuing their new currency, but before they can even catch their breath from dealing with the last international crisis, a new one arises in the form of the conquered Yamato Empire's Princess Kaguya. When she pleads for the salvation of her country from the Freyjagard Empire under the pretense of the Seven Luminaries' hallowed ideal of "equality for all," the prodigies may have no choice but to renew tensions with their former foe.