One Punch Man follows the life of an average hero who manages to win all of his battles with only one punch! This ends up being the cause of a lot of frustration as he no longer feels the thrill and adrenaline of fighting a tough battle. Maybe all of his rigorous training to become strong wasn't worth it. After all, what's so good about having overwhelming power?
Power of the verse
Most relevant characters are casual City to Mountain level. And the stronger fighters have shown to be Large Island+ to Multi-Continent level with ease. Lord Boros even stated that he would have destroyed the Earth in the anime, which the manga's guidebook supported. A good amount of heroes/monsters are also thousands of times faster than sound, with the top tiers being Sub-Relativistic or higher.
Supporters / Opponents of the verse
Not Jim Sterling
The Queen Diclonius
Sirius The EM Troll