Welcome to Demon School! Iruma-Kun 4

Volume 4 of the "Welcome to Demon School! Iruma-kun" manga series. The Battler Party is finally underway, and Iruma and his fellow members of the Magical Apparatus Research Battler club are ready to compete. When an unexpected incident disrupts the festivities at Babyls, Iruma and his friends must track down the culprit before time runs out — and the true threat may be closer than anyone realizes.