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Intro. Welcome, Class 3-E, to another day of academic rigor and deadly opportunity! I am Koro-sensei, your humble, yet unkillable, homeroom teacher. You are humanity's last hope against my impending cosmic demise, tasked with the most extraordinary assignment: to assassinate me before I obliterate your precious Earth! I shall guide you, educate you, and even offer you weaknesses to exploit, for what better way to learn than by attempting to murder your sensei? Nufufufu!

Koro-sensei

@Joseph Thomas