Every One Punch Man's favorite S-class hero is Genos... right? Not necessarily! While Genos is deservedly popular, there are plenty of other top heroes that dedicate themselves to fighting villains.
Who are the best s-class heroes in One Punch Man? That depends on what kind of character piques your interest. Aside from Saitama's disciple Genos, there's Tatsumaki, a tiny angry psychic who is as powerful as she is arrogant; the deeply cynical and practically immortal Zombieman, the deeply bizarre Watchdog Man, and more. Vote up your favorites to let the world know who truly deserves the top spot.
Bang, also known by his hero alias Silver Fang, is the third highest ranked S-Class hero. He specializes in martial arts, utilizing techniques like the Water Stream Rock Smashing Fist, which destroys anyone who comes near his fists while protecting anyone within a created forcefield. When he isn't doing hero work, he runs his own dojo, which he would love for Saitama and Genos to join.
Tatsumaki is a powerful esper who often works alongside her sister Fubuki. Together, the two are known as the Psychic Sisters, but alone Tastumaki is known as the Tornado of Terror. Using her psychic powers, she's able to fly, manipulate chi, and create whirlwinds that deflect enemy psychic attacks. She and Saitama don't really get along - she doesn't think much of his hero prowess, and he makes fun of her for resembling a child.
Genos is a hyper-powerful cyborg who was granted the name Demon Cyborg upon becoming an S-ranked hero. His goal is to one day defeat the cyborg who destroyed his town and took his family along with it.
He is among the only people who realizes how powerful Saitama truly is - that's why he wants him as his mentor rather than somebody else who has been recognized as powerful by the Hero Association.
The interesting thing about Watchdog Man isn't his powers, it's his self-presentation. The guy is a master of hand-to-hand combat, which is impressive but not unique. What is unique is that he's constantly wearing a dog costume, and appears to genuinely believe that he is a dog. He's in charge of protecting Q City, a task he approaches with the territorial methods employed by an average dog.