The Bugle Call: Song of War manga volume 4 features story by Mozuku Sora and art by Higoro Toumori.

The Pontiff's expedition to Gallia has reached the capital of Limoges. The city is held by the forces of the Looking Glassists, and defended by the Looking Glass herself - only Zoe has the power to even attempt to take her on. If Zoe fails, so does the entire operation. Though the Looking Glass will give her enemies no quarter, she also sees something of herself in Zoe. During the battle, Luca encounters a mysterious interloper, and discovers more secrets of the Branched - including a new phase of their development, the Flowering...