Akashic Records of Bastard Magic Instructor Vol. 11 (manga)

A DEADLY WALTZ

Amidst the tumult of the school's grand ball, the deadly Eleanor suddenly appears before Glenn, offering only hints and insinuations. As the dance contest continues, the stage is set for an inferno: the elite war-mages of the Special Missions Annex face off against killers from the Researchers of Divine Wisdom. The assassins picked their targets well, and even if the Annex is split up, they can't afford to lose a single fight!