Assassination Classroom, Vol. 20

The battle for Koro Sensei's life against a multinational operation's soldiers and weaponry is difficult enough, but now his creator, mad scientist Yanagisawa, and his former protégé, Grim Reaper II, join the battle to destroy him—and they've both had major enhancements! But the stakes abruptly change when a 3-E student is fatally caught in the crossfire… If there's one thing that enrages 3-E's teacher, it's harming—let alone killing—his students! Koro Sensei's fury and ingenuity know no bounds, even as fate inexorably catches up to him…

Volume 20 of the Assassination Classroom manga series by Yusei Matsui.