Corpse Party: Blood Covered, Vol. 5 — Makoto Kedouin

The end is nigh!
Behind the truth of Sachiko's death lies a cruel and tragic past...The students of Class 2-9 struggle to hold on to their sanity as they fight both the ghosts of the school and the ever-encroaching Darkness that seeks to turn them against their friends. If they can't solve this mystery soon, it'll be too late!
When living is this hellish, is death the only way out...?