Our Last Crusade or the Rise of a New World, Vol. 4 (light novel) — Kei Sazane

Thanks to Rin's interference, Iska has been taken captive in the Nebulis Sovereignty under Alice's guard. But the two fated rivals have little time to sort out their feelings, as they learn that the infamous sorcerer Salinger has escaped imprisonment…and Alice must do everything she can to stop him from gaining what he seeks. Against an opponent with the fearsome ability to steal astral powers, will mage and Imperial soldier join hands once again?