Chapter 21: Giant Meteor

Collected in Volume 4 and belonging to the Giant Meteor Arc, this chapter opens on the aftermath of the hero rankings before pivoting to a planetary emergency. A massive meteor bears down on Z-City, and the Hero Association scrambles to respond while most of its S-Class ranks refuse the assignment. What begins as a mundane conversation between Saitama and Genos escalates into a race to spare an entire city from destruction.

Genos reads out that Saitama has climbed from dead last to 342nd place, though the update fails to impress him. Genos then reveals his own 17th ranking and 6th-place finish in the popularity vote, praising his master along the way. Summoned to the Z-City branch, Genos meets Bang, the third-ranked S-Class hero, and learns that the building has been evacuated because a Dragon-level meteor is inbound. Bang deems stopping it impossible and urges retreat, but Genos refuses to abandon the citizens.

Deploying his prototype Arms Mode, Genos positions himself near the projected impact zone, only for Metal Knight's remote-controlled robot to arrive and loose a barrage of missiles that fail to slow the rock. Bofoi admits he came merely to field-test a new weapon and prefers to be called Metal Knight. As Genos exhausts himself in a desperate final blast, Bang shields him. Saitama then races in, hurls himself skyward, and drives his fist clean through the meteor, splitting it apart.

The shattered meteor rains debris across Z-City, flattening numerous buildings, including the rooftop where Genos and Bang stand, before Saitama lands and strolls off without concern. Serialized across four parts in February and March 2013, the chapter runs 183 pages online and 80 in volume form, carries Genos as its cover character, and was adapted into Episode 7 of the anime.