The Ultimate Master

To register as official heroes, Saitama and Genos must clear both a physical trial and a written exam. Saitama overwhelms the physical portion and outshines every other applicant, but his written score drags him down until he squeaks through by a single point and is slotted into C-Class. Genos posts a flawless result and is placed straight into S-Class.

Out of the entire applicant pool, the two are the only ones assigned to a class taught by Sneck. The instructor's confidence outpaces his skill, and when he singles Saitama out for ignoring the lesson, he only embarrasses himself against a far stronger student.

Eager to test his latest upgrades, Genos asks Saitama to spar. Still doubting that ordinary exercise built such power, Genos suspects a hidden secret even Saitama may not grasp. He throws everything he has while Saitama barely engages, so Genos presses him to go all out. The moment Saitama does, the match ends without a single blow landing, and Genos accepts that his rival occupies a level unreachable through training alone.

The pair then head to an udon shop for an eating contest, where Genos finishes with ease while Saitama nearly collapses. Sweet Mask appears and pulls Genos aside, congratulating him and welcoming him to the S-Class ranks, to Genos' surprise.

The adaptation adds material absent from the manga, including a Hero Association meeting, the sense that Genos is under observation, and the udon-shop encounter with Sweet Mask. Shot put, whack-a-mole, and the punching machine are anime-only exam events, and Saitama briefly mistaking his C-Class placement for S-Class is an anime-only gag. In the source, Saitama lifts the barbell with both arms and a heavier load that cracks the ground, whereas the anime uses one arm. The clash between Saitama and Genos is slightly reworked, and the aftermath plainly shows the cliff damage that the manga rendered as a dust cloud. Sneck delivers the post-credits monologue.