Saitama’s overwhelming strength remains largely unrecognized for most of the series, particularly before he officially became a professional hero under the Hero Association. His tendency to avoid claiming credit for his victories contributes to this lack of recognition.
However, a handful of individuals have either sensed his incredible power or witnessed it firsthand. Even then, skepticism persists, with some doubting his abilities due to their own biases, ego, or disbelief in his low hero ranking and seemingly basic training method.

Bang
During the Giant Meteor incident, Bang realized just how formidable Saitama truly was. Observing him reduce an enormous meteor to rubble with a single punch was enough proof that the Caped Baldy possessed unimaginable strength.
Busho
At first, Busho hesitated to deploy Saitama against a Disaster Level Demon threat. However, he became one of the earliest members of the Hero Association to recognize Saitama’s true potential after reviewing his hero records.
Alongside Jinzuren, Busho sought to personally assess Saitama’s power, which became evident after his effortless victory over the Deep Sea King. Following this triumph, Busho, along with several other key officials, strongly advocated for Saitama’s promotion within the Hero Association.
Bofoi
While reviewing security footage of the newly rebuilt City A, Bofoi found himself puzzled by how an unknown hero singlehandedly dismantled his robotic enforcers—machines designed to neutralize even Demon Level threats.
This unexpected display of power sparked his curiosity about Saitama, leading him to investigate further. After going through Saitama’s rapid rise in notoriety, Bofoi speculated that the hero could potentially pose a challenge to his larger schemes.
However, after the security breach that led to high-level monsters escaping during his clash with Tatsumaki, Bofoi developed resentment toward Saitama. The damage done to the facility he designed negatively impacted his reputation, making him see Saitama as a liability.
Despite this, he continued to monitor the Caped Baldy closely, keeping an eye on those who could stand in the way of his ambitions.
Blast
Saitama and Blast first crossed paths in the underground of Z-City, where Blast initially dismissed him as unremarkable. However, that perception changed drastically when Saitama later confronted Garou, who had been granted divine power.
Witnessing the force of their clashing fists, Blast immediately recognized the potential destruction their battle could unleash upon Earth. Shocked by what he had just seen, he acted quickly to teleport both fighters into space.
However, due to Saitama’s time-traveling actions, which erased the disastrous future from ever happening, Blast lost all memory of this encounter. Nevertheless, he was still present when Saitama defeated Garou with a single punch.
When recounting the incident to Sitch, Blast admitted that he could not determine the true extent of Saitama’s strength.
Sitch
During a crisis meeting after the downfall of the Monster Association, Genos recounted everything that had transpired in the erased future, including how Saitama had been the one to defeat Garou. Initially, Sitch found this hard to accept.
However, with Blast confirming that he had witnessed Saitama’s power firsthand, Sitch could no longer deny the truth.
Tatsumaki
Saitama’s strength became evident to Tatsumaki when he interfered as she attempted to discipline the Blizzard Group. Their encounter quickly escalated into a battle, where Tatsumaki realized that he could withstand her powerful psychic attacks.

Though she remains stubborn in believing she is the stronger of the two, she acknowledges that Saitama is no ordinary hero.
Zombieman
Hearing about Saitama’s feats directly from Genos, Zombieman struggled to accept the idea of someone possessing such overwhelming strength. However, the more he learned, the more he began to suspect that Saitama’s abilities might truly be beyond comprehension.
Fubuki
Her first meeting with Saitama was motivated by her desire to recruit him into the Blizzard Group, fearing that his rapid rise in rank would threaten her position. But after experiencing his strength firsthand, she quickly realized that he was far beyond her level.
Saitama effortlessly dodged her attacks and scolded her for looking down on lower-ranked heroes. The moment that sealed her understanding of his capabilities was when he swiftly defeated Sonic with his Serious Side Hops.
Despite this revelation, Fubuki remains persistent in trying to bring Saitama into her group, sometimes resorting to persuasion or manipulation to achieve her goal.