Saitama

Saitama is the main protagonist of One-Punch Man and the single most powerful being in the series, a hero who can end any fight with a single punch. That overwhelming strength has left him unable to feel any real thrill in battle, trapping him in a self-imposed existential crisis he can't quite shake.

Once just an ordinary, unemployed man who decided to become a hero for fun, Saitama eventually registered with the Hero Association after realizing nobody recognized his efforts. Within the organization he's known by the hero name Caped Baldy and currently holds A-Class rank, though his unassuming appearance and indifferent attitude toward danger mean most people badly underestimate him. He now mentors Genos as his disciple and counts King among his few close friends.