This is book number 1 in the One-Punch Man series.
— Viz Media
When monsters mysteriously begin to appear all over Z-City, the strongest heroes must rise in order to defeat them. The strongest hero of all is a man named Saitama, who is able to knock out the deadliest of monsters with one punch! — Elizabeth Bryan
A laugh-out-loud manga comedy that pokes fun of any superhero story, origin situation, battle anything, while remaining utterly serious. Staring bored, overpowered, self named hero Saitama. You might want some privacy for this one, you will end up braying like a donkey. — Firdous Madany