Black Butler, Vol. 18 by Yana Toboso

Their elaborate schoolroom deception at an end, Earl Ciel Phantomhive and his peerless manservant, Sebastian, finally hit upon the truth behind the incident of the vanished students at Weston College. Just what tragic steps did the elites of the school, spurred on by their overwhelming sense of justice, take to stamp out the bullying with which the halls of their institution had run rife?! What began as a seemingly simple case of missing persons goes round and round, spinning out of control into a great menace, one capable of perplexing even a devil of a butler...