The Bugle Call: Song of War. Volume 3: Mozuku Sora

A young bugler with supernatural powers is swept up into an epic struggle for the fate of the world. Cry havoc and sound the song of war!
In Arboral Year 1294, the world is dominated by nine massive towers known as the Spires—remnants of an advanced civilization, they are filled with lost secrets and powerful knowledge that nations struggle to possess. Luca is a bugler in a mercenary company who wants nothing more than to leave the battlefield behind and become a true musician, a maestro. But marked as one of the enigmatic Branch-hexed, and gifted with the strange ability to see the sound of his instrument, Luca finds himself drawn reluctantly into a war of epic proportions!
The Holy Realm’s Branched squad takes on a new mission to the kingdom of Gallia, the Land of Mirrors. There, they will seek the aid of its protector, the powerful Branched known as the Looking Glass, to help them defeat the Garland. But Gallia is embroiled in a civil war, and convincing the Looking Glass will mean taking sides in a deadly conflict. What the Looking Glass wants in exchange for her help may be more than Luca is willing to give up, and he and his companions must face a challenge that will take all their skill and cunning—and perfect timing—to overcome.