Characters aware of Saitama's power

For all his standing as comfortably the mightiest figure in the story, Saitama's strength goes mostly unnoticed, especially in the days before he registered as a professional hero, since he never lays claim to what he accomplishes. A small number of characters come to understand it, either by sensing his latent potential or by watching him in action, yet even some of those hold onto doubt, whether out of pride, prejudice, or skepticism toward his low rank and famously simple training routine.

The figures with the deepest understanding tend to be those who have watched Saitama close out fights in an instant or felt the sheer scale of his aura. Genos took him as a master after being saved from Mosquito Girl, while Bang, King, Fubuki, and Suiryu each came around after witnessing effortless victories, from splitting a meteor to flattening tournament champions. A rare few, such as Boros and Orochi, could feel his limitless power the moment they faced him, and Tatsumaki grudgingly conceded his strength after clashing with him. Others learned through raw defeat or observation: Speed-o'-Sound Sonic swore lifelong rivalry after losing, Garou faced him as the embodiment of unfairness, and Blast, Flashy Flash, and Empty Void recognized that his fists could even knock the borrowed power out of God's minions. Dr. Kuseno knows of him only through Genos's endless praise, and the entity called God itself came to view Saitama as a threat worth destroying.

A larger group senses that Saitama is unusual without fully comprehending it. Carnage Kabuto instinctively recoiled from him before his rage buried the fear, and Bakuzan assumed a cheap trick had beaten him. Several Hero Association staffers, among them Jinzuren, Busho, and Sneck, took note after his record-breaking fitness exam or his rout of the Deep Sea King, though not all were convinced. Foes such as Geryuganshoop, Hammerhead, Phoenix Man, Manako, and Nyan each felt his strength firsthand and often fled or surrendered. Metal Knight quietly kept him under surveillance as an unknown variable in his plans. A whole cluster of witnesses, including Blue, Suiko, Butterfly DX, Chain'n'toad, and the members of the Hero Name Victims Association, came to recognize his power together after watching him erase the Dragon-level Mirror in one punch in Y-City.