Summary of One Punch Man (OPM) Chapter 21
Chapter 21 opens with a hilarious yet intense citywide panic as monsters keep popping up everywhere. Saitama and Genos get called into action when a sea monster invasion begins, led by the terrifying Deep Sea King. The tension builds as we see how much stronger this villain is compared to past threats. Genos leaps into the battle with his usual fiery resolve, showcasing his incredible speed and power, but it becomes clear even he is outmatched. Meanwhile, Saitama is busy doing errands, completely unaware of the chaos unfolding. Fans will love the sharp contrast between the desperate, high-stakes fight and Saitama’s calm indifference. We also meet more heroes like Stinger and Lightning Max, who give it their all but face brutal defeat. This chapter beautifully balances action and comedy, making you laugh at the absurdity while genuinely worrying for the characters. By the end, you are on the edge of your seat, wondering when Saitama will show up to turn the tide.