Our Last Crusade or the Rise of a New World, Vol. 7 (manga)

Determined to protect Sisbell, Iska clashes with a mysterious witch who suddenly appeared before him! Tensions were already high between Alice and Sisbell, but when Elletear, the oldest of the three sisters, gets involved, this sibling rivalry starts to really heat up! Somehow, Iska finds himself at the heart of the conflict, which promises to be more intense than any war he's ever served in...