In One-Punch Man, Vol. 14: The Depths of Despair, the martial arts tournament takes a dark turn when the monster Goketsu arrives with a sinister plan. Goketsu's intent is to transform the participants into monsters using monster cells, and the tournament champ Suiryu soon finds himself battling against these newly monsterized fighters.

As Suiryu confronts one monstrous opponent after another, the situation looks increasingly dire, until an unexpected hero arrives to lend assistance. This volume continues to blend intense action with comedic moments, characteristic of the One-Punch Man series.