Chapter 120

Inside the Monster Association corridors, Saitama matches Flashy Flash's pace so easily that the S-Class hero cannot understand it. Mid-run, Saitama notices the same monster body and the same passage cycling past over and over and asks whether they have gotten lost, but the annoyed ninja stays silent.

On the surface, several A-Class and B-Class heroes fend off monsters to keep Waganma safe. Once the attackers fall and every entrance is sealed, Poison catches sight of a tall cat-like shape and orders One Shotter to shoot. Nyan catches the round on his claw and sends it back, grazing the sniper's skull. Delighted to run into so weak a group after meeting Saitama, he says he wants to play, blurs into the crowd, and cuts down several heroes in one motion. He calls himself a cadre of the Monster Association while quietly noting he has already left, and thinks back on his days as a plain cat that shredded toys until they broke, now free to indulge himself.

Sekingar tells Food Battler Futoshi to rush Waganma clear. As Feather and Poison steady themselves, Nyan grins and declares the game is to shred Waganma while the rest look on. Mizuki turns her medal into a discus and hurls it as Green ties the cadre down with vines, but Nyan bites the disc apart. Poison's strike snaps against Nyan's eyelid, and when Feather and Shadow Ring attack, the cadre slips the vines, breaks their blades, and drops them both. With the survivors stunned, Nyan turns to the terrified Waganma while Futoshi keeps eating to restore his strength.

Saitama realizes Flash has been leading them in circles. Nyan reaches the surface, deflects a sniper's bullet, and wounds Needle Star, Gearsper, Twin Tail, and Jet Nice Guy at once. He shatters Mizuki's discus, snaps Poison's blade, and defeats Feather and Shadow Ring while announcing his goal of killing Waganma for an audience.

This chapter is part of the Monster Association Arc and appears in Volume 25 with no webcomic basis. It carries an original release of September 6, 2019 and was revised on February 27, 2022 for Volume 25, running 22 pages. Its cover character is Saitama, and the volume bonus page shows Sonic kneeling with a kunai, an irritation mark on his head as he complains about getting no screentime during these chapters.