Killing Time in Homeroom

An extraterrestrial creature steps in front of class 3-E at Kunugigaoka Junior High and greets the students, who immediately open fire with pellet guns. He glides through the barrage untouched, leaving the room rattled. The situation traces back to a startling event: the being reshaped the moon into a fixed crescent, demonstrated powers strong enough to hold the planet hostage, and announced a plan to obliterate Earth within a year. As a condition, he swore to run this one classroom without ever harming a pupil. In response, the Ministry of Defense under Karasuma offered the students a ten-billion-yen prize for whoever finishes off the teacher first.

When the midday break arrives, the creature streaks off to Sichuan for a plate of mapo tofu. In his absence, Terasaka corners Nagisa and hands him a scheme of his own for cashing in. Following Nagisa's earlier attack with an anti-teacher blade, the boy embraces the creature to reveal a grenade packed with special pellets, which Terasaka detonates by remote. The teacher survives yet again, having simply shed a monthly layer of skin. Enraged, he zips across the country gathering the nameplates from every student's home, warning that only the pupils are off-limits. He commends Nagisa's smooth attempt but rebukes Terasaka's group for gambling with a classmate's safety, then Kayano settles on a name for him.

To prove the pellets cannot stop him, the creature severs his own arm and regrows it in front of the class. During a flashback, Karasuma explains the mission, lunges with a knife, and instead has his eyebrows neatly trimmed, exposing the teacher's top speed of Mach 20. Nagisa waits for the being's face to shift to relaxed pink before striking, setting up Terasaka's grenade trap. The failed blast triggers the teacher's pitch-black fury and the nameplate roundup that pins the class into taking the assassination seriously. In the closing scene, Kayano christens him Korosensei, a play on korosenai, meaning unkillable, joined with sensei.

This is the first chapter of the manga, running fifty pages and originally carried in the thirty-first issue of 2012 on July 2 of that year. VOMIC voiced adaptations of the installment ran as weekly pieces on the Japanese variety program Sakiyomi Jan Bang! across January 2013, went up on Shueisha's VOMIC site through February 2013, and reached YouTube via the official Shonen Jump channel on July 8, 2013.