The Bugle Call: Song of War manga volume 3 features story by Mozuku Sora and art by Higoro Toumori.

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.