Young Magician Vol 13

From the CMX edition

Besieged by attacks from hordes of magicians under the direction of Ark - the Magician King - Ibuki, Carno and Levi have gone into retreat. But they are not likely to find much peace sequestered in an ancient fortress built by a necromancer, as the remains of many souls are sealed inside. The energy from these souls has rattled Carno, and it may be too much for his volatile personality.

Source: Anime News Network Encyclopedia