Volume 10

"Fighting Spirit" (気合い, Kiai) is the tenth volume of the One-Punch Man manga series.

Summary
A single man arose to face the evil threatening humankind!

His name was Saitama. He became a hero for fun!

With one punch he has resolved every crisis so far, but no one believes he could be so extraordinary strong.

Together with his pupil Genos (Class S), Saitama has been active a hero and risen from Class C to Class B.

One day the seer predicts a great danger to Earth and dies. Is the increasing number in catastrophes in recent years an omen of this great danger? When the Hero Association seeks cooperation from ne'er-do-wells, a man named Garou, who admires monsters, shows up and begins hunting the heroes instead!

ONE
Saitama! Genos! Monsters!? They're moving around and talking!

Yusuke Murata
I decided to become a proper old man, so I stopped dying my gray hair.

Volume Notes

 * On the inner book cover, the name of the mall that Saitama bought the bananas for Mumen Rider from is different from the plastic bag at the hospital, they were supposed to match. Murata planned to fix it on the new printing of the tankōbon.
 * For the picture which Fubuki and Tatsumaki shops together, Murata regrets not drawing the sailor clothes for Fubuki, because when Fubuki was young, she should look like a normal kid like any other.