Chapter 15: Hobby and Work

Speed-o'-Sound Sonic opens his fight by flaunting his velocity, darting and leaping in blurs around Saitama while taunting him. Saitama, unimpressed, simply turns his head and asks the ninja to move along. Thrown off, Sonic spins into a kick, only to slam his groin straight onto Saitama's waiting fist. Moments later he stands doubled over in pain, legs pressed together, and declares Saitama his rival before withdrawing.

Back at the apartment, Saitama grumbles to Genos that Sonic had never even heard of him, a fresh reminder of his obscurity. Genos brings up the National Super Hero Registry, explaining that anyone left off its rolls goes unrecognized as a hero. The system launched after Saitama began his career, so the news is new to him. The two settle on signing up for it together.

Sonic loses his second bout with Saitama in embarrassing fashion, taking the outstretched fist to the crotch, yet still names Saitama his rival. Saitama learns his lack of fame stems from never joining the Hero Registry, which was founded after he became active. He and Genos decide to enroll and gain official recognition.

The chapter belongs to the Paradise Group Arc and appears in Volume 2. Its events are covered in Episode 4 of the anime adaptation. Agoni appears in a debut role, and the cover features Sonic alongside Genos and Saitama. Viz Media released the chapter under the title Fun and Work.