One-Punch Man Manga Volume 11 features story by ONE and art by Yusuke Murata.

While Saitama's distracted at a martial arts tournament, Centichoro, a threat-level Dragon monster, attacks! Metal Bat engages it in battle but struggles against its gargantuan size. The monster knocks him into the distance and right into the path of hero-hunter Garo!

One-Punch Man Manga Volume 12 features story by ONE and art by Yusuke Murata.

At the martial arts tournament, Suiryu of the Dark Body Art shows promise with his outstanding strength. But outside the stadium, a large number of monsters are pushing the heroes, even Genos, to their limits! Back inside and unaware, Saitama approaches his match against Bakuzan!

One-Punch Man Manga Volume 13 features story by ONE and art by Yusuke Murata.

Class-A heroes struggle in their fight against the giant monster Multieyed Octopus. Wait, is that Class-S hero Flashy Flash joining the fight?! Unfazed, the Monster Association continues ramping up its attacks, but its goal remains a mystery. Meanwhile, the martial arts tournament reaches the semifinals!

One-Punch Man Manga Volume 14 features story by ONE and art by Yusuke Murata.

The monster Goketsu appears at the martial arts tournament, and in an attempt to turn its participants into monsters, he gives them monster cells. Tournament champ Suiryu fights the newly monsterized fighters one after another, until a certain hero rushes to his side to help!

One-Punch Man Manga Volume 15 features story by ONE and art by Yusuke Murata.

Despite just finishing a martial arts tournament and immediately dealing with the Monster Association invasion, Saitama is still so incredibly strong that he feels empty inside. King lectures him on how to live like a hero, but it doesn’t help. Meanwhile, servants of the Monster Association close in on Speed-o’-Sound Sonic!