Saitama is not a typical underdog. He is a post-game character playing the tutorial. His internal conflict is not "Can I beat the bad guy?" but "Is there any meaning to beating the bad guy?" He suffers from depression masked by apathy. In a brilliant turn, the series uses his overwhelming power not to create action, but to defuse it. The most dramatic moments in One Punch Man often happen after the punch, when we see Saitama’s empty, bored face looking at the dissipating cloud of what used to be a city-destroying horror.
In the vast landscape of anime and manga, the "Shonen" genre is defined by a simple, effective formula: a young, ambitious protagonist faces increasingly powerful enemies, suffers defeat, trains rigorously, overcomes their limits, and eventually achieves victory through sheer willpower and growth. It is a narrative structure that has built empires like Dragon Ball , Naruto , and One Piece . One Punch Man
In a world where other heroes like the S-Class King or the cyborg Genos take every threat with life-and-death seriousness, Saitama is not a typical underdog