ワンパンマン 21 [Wanpanman 21]

Heroes from the Hero Association push into the Monster Association’s underground base to rescue a hostage and confront the monsters waiting inside. The volume splits its attention across multiple S-class fighters, with the strongest heroes advancing deeper while lesser ranks struggle behind them.

Two major threads dominate: Flashy Flash cutting through high-speed ninja opponents, and Child Emperor using gadgets and strategy against increasingly dangerous monsters while trying to complete the rescue. Their battles unfold alongside other hero-versus-monster clashes and repeated reveals of enemy adaptation and escalation.

The volume ends with the conflict still unresolved, leaving the larger raid and rescue mission in progress. Readers repeatedly note the absence of the title character, while the story instead emphasizes supporting heroes, power displays, and a cliffhanger sense of escalation.