Welcome To Demon School! Iruma-kun 4

"The much-awaited Battler Party is finally here, and Iruma and the demons of the Magical Apparatus Research Battler are ready to blast the competition away. But when a surprise shakes Babyls to its core and threatens to upend all the festivities, it's up to Iruma and his friends to find the culprit before time runs out. Unfortunately for them, true evil may be lurking closer than they think..."--Provided by publisher.