In Volume 2, Saitama finds himself growing bored due to the lack of opponents who can offer him a true challenge. Despite his immense strength, he struggles with the monotony of effortlessly defeating every enemy he encounters. However, his passion for heroism and his desire to find a worthy adversary remain undeterred. As he encounters more villains and monsters, he begins to long for the excitement and thrill of a genuine fight.
This volume also introduces a diverse cast of characters, both heroes and villains, each with their unique personalities and abilities. Genos, the cyborg hero who was defeated by Saitama in the first volume, becomes a central figure as he seeks to improve his abilities and unravel the mystery behind his own transformation. In this volume, we are also introduced to the deeper characteristics of the higher tier heroes such as King, Metal Bat, Silver Fang (Bang), Tatsumaki, also called Tornado of Terror, etc.
He is also met by supposedly strong opposition that high level heroes were struggling against such as, Beast King, Armoured Gorilla, Genus, etc, all who defeated other A Level heroes, who Saitama was able to defeat, of course in a single punch.As the story unfolds, readers are treated to a blend of intense battles, comedic moments, and reflections on the nature of heroism. Saitama's nonchalant attitude and deadpan expressions contrast brilliantly with the chaotic and colorful world around him, creating a perfect balance between action and satire.