Young Magician Vol 12

From the CMX edition

A showdown looms with Ark, the nearly invincible Magician King. Carno and Ibuki join a group of other powerful sorcerers who go to the place where Ark is supposedly imprisoned. After a search of the dungeons comes up empty, it isn't long before the band of magicians finds themselves under attack. Was Ark really setting up Ibuki to be his successor, or was that all part of some elaborate hoax?

Source: Anime News Network Encyclopedia