There are only two people who currently may be stronger or equal to Saitama: God and Blast. Yes, if anyone can match him, there will only be one person who can do it. Saitama and the entire series will be ruined if there are multiple people equal to him.
He had almost completed his meal, and Fubuki took her seat next to him. The Caped Baldy ordered some fries for her, leaving Fubuki surprised that he was making a kind gesture towards her. The fanbase thought Fubuki had romantic feelings towards Saitama due to this interaction.
Through various circumstances, he forms friendships with Mumen Rider, Bang, King, Genos, and Blizzard. His superhero name in the association is Bald Cape (ハゲマント, Hagemanto, Anime: Caped Baldy). Saitama is voiced by Makoto Furukawa in the Japanese version and by Max Mittelman in the English dub.
Blast is widely known as the S-Class rank 1 hero and the Hero Association's most powerful asset—as Saitama's strength is not yet widely recognized. Full details about his abilities and whereabouts were unknown for most of the series.
God is the overarching antagonist of the Monster Association arc in the manga One Punch Man and possibly the entire series. It is a mysterious entity that desires the eradication of all humanity. However, it chooses to remain hidden for the time being and instead grants powers to others who share its thoughts.
Lord Boros is the mirror antagonist to Saitama. Like Saitama, he was too powerful to find a worthy opponent and became extremely bored. Boros serves as a reminder of what Saitama could be if he didn't have a heroic foundation.
Blue is a teenager of roughly average height and muscular build with light hair that falls over his face in bangs. His eyes have multicolored irises, being light near the center but dark towards the outside, resembling his father Blast.
The big reveal is that when Saitama finally meets him, he will put two and two together and find out that Blast is his dad. Yes, he is supposed to be an elusive character, but especially with the other stuff we know about him, this just makes sense.
Genos has the appearance of a 19-year-old boy with a face and hair similar to that of a human.
Marugori (マルゴリ, Marugori), also called Beefcake, was a human who drank the Biceps Brachii King steroid developed by Fukegao, which turned him into a mutated giant.
Boros was the only one that was acknowledged by Saitama, who said that he was a strong fighter. Since then, every villain he faced has been beaten within a punch or two and Saitama hasn't worked up a sweat during any of these fights. Even in the manga, Saitama was able to beat Orochi with ease.
Despite his nickname, Saitama doesn't always defeat his opponents with a single punch. In fact, occasionally, he unloads a flurry of attacks. As the titular character of One Punch Man, it is often expected of Saitama to finish his enemies in no more than one punch.
Saitama is a seemingly unbeatable hero who can defeat any opponent with just one punch. While Gojo's abilities are impressive, it's hard to imagine even he could withstand a punch from Saitama. In a battle between the two, it's likely that Saitama would overpower Gojo with his raw strength.
In One-Punch Man's case, the tone of the manga and Saitama's oblivious attitude make it very unlikely that the protagonist will ever end up in an actual romance.
Saitama's Potential for a Love Life in One-Punch Man
He has been slowly rejoining the world and has developed more relationships through the course of the series, but he is still far too detached from his own emotions and has shown little desire for companionship, much less a romantic partnership.
Genos has become Saitama's companion and the closest thing he has to a best friend. He is also the person who he spends most of his time with, since Genos moved into Saitama's apartment to live with him.
Fubuki is her real name.
He is immortal, so he must live forever... His power isn't all about his body, but he is rather healthy, considering he's still doing his workout, so i reckon somewhere above 100 years, considering he's as normal as everyone else when it comes to basic human things.
Saitama has never been shown to be sick or even affected by sickness.
After receiving what seem-to-be a fraction of power from "God", Garou mutated, gained various powerful abilities, and became capable enough to fight against and even force Saitama to get serious before ultimately being defeated.