In Volume 4, the arrival of a new teacher, Irina Jelavić, adds chaos and charm to Class 3-E. As a professional assassin disguised as an English teacher, she attempts to kill Koro-sensei using seductive tactics. However, her methods clash with classroom discipline, leading to humorous and dramatic situations. The students observe different assassination styles and learn valuable lessons about professionalism. Koro-sensei continues to surprise everyone with his teaching brilliance. Emotional development becomes central as the class reflects on their goals. The storyline balances action with school-life comedy perfectly. Character backstories receive more attention, building deeper connections. The tension between Earth’s survival and daily exams intensifies. Volume 4 keeps readers engaged with unpredictable twists and heartfelt moments.