Sensou Kyoushitsu

In Arboral Year 1294, the world is dominated by nine massive towers known as the Spires, remnants of an ancient civilization. Filled with lost secrets and powerful knowledge, nations struggle to possess them. 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!

(Source: VIZ)