Known to many as the man with the most redundant name ever, Speed of Sound, or Sonic for brevity, is one of the fastest characters in the series. Though he can’t really move fast enough to cause sonic booms, he is able to sprint across a long distance at extremely high speeds. When he attacks someone with his sword, it is reminiscent of a samurai using an extremely quick slash of Iaido as he appears behind his opponent after attacking. He is usually calm in battle, mostly due in part to his ninja training. However, hidden within him is a battle maniac that simply craves for battle. When he meets Saitama, the hero of the series, none of his attacks have any effect on the caped baldy. This gets his blood pumping as he enjoys fighting those who are stronger than him. Despite his skills however, he ranks quite low on the power chart. That just shows how strong some of the characters in One Punch Man are.

Though he is the weakest hero on the S-rank list, Puripuri Prisoner’s strength is still nothing to scoff at. With rippling muscles from top the bottom, Puripuri Prisoner is built like a tank and he acts like one as well. Striding into combat with nothing but his bare fists, he blows away the opposition with his raw strength and musculature. Puripuri Prisoner also has a mode named Angel Style, in which he increases his strength to its maximum limit, bringing them beyond the threshold. It has the…unfortunate side effect of increasing his muscle mass, causing all his clothes to be torn off completely. Nevertheless, when in this mode, he’s shown to be many times stronger and has even caused severe damage to the Sea King, someone Genos had trouble with. Like him or hate him, Puripuri Prisoner is one tough son of a gun.

Often shown to be a callous individual, Bofoy’s hero name is “Metal Knight” because of his preference in using a robot that looks precisely what the name implies, a metal knight. Bofoy is a true scientist at heart, trying out different configurations with his robot or letting a bunch of hooligans steal his experimental suit just to see how far they can be pushed. His personality aside, an individual with access to all the technology he has at his disposal is not to be reckoned with. He has enough tech in his arsenal to arm an army and with the amount of robots he has, he could easily cause a disaster rating to rise in the cities of A-Z. Bofoy is definitely someone you don’t want to get on the bad side of.

A fan favourite, Genos is a cyborg who works together with his professor to find out who attacked his town and killed his whole family. One day, he runs into Saitama, who handily dispatches every foe in his way with a single punch. In awe of his power, Genos forces Saitama to apprentice him in hopes of somehow getting some of that strength for himself so that he may avenge his family eventually. But that doesn’t mean Genos is weak. Though his ranking on the S-rank list is still rather low, that can be attributed more to experience than any weakness on his part. With cybernetic enhancements boosting his physical abilities to the max, Genos moves at inhumane speeds and attacks with inhumane strength. On top of that, he has multiple projectile type attacks that can cause extreme devastation to his enemies. Out of all the heroes who attacked the Sea King, he was the one who did the most damage in the end, barring Saitama. With a thousand and one ways to kill anyone, it's doubtful anybody wants to cross him anytime soon.

Go back to the title, realise it says characters instead of heroes, then we can continue on with the article. Because how can we not include this beast when it comes to the strongest? The Sea King comes from the same cliché that perpetuates the entirety of the series, from the Ground King to the Air King to the Sea King. Arguably, the Sea King sounds like the strongest. When battling Puripuri Prisoner, he had some difficulty. But it was revealed that he wasn’t even in his full strength as it wasn’t raining. When the rain started pouring down, it became all over for the heroes fighting him. They were immediately batted aside and squashed under his heel. Only the timely intervention of Saitama saved them from him. And well…comparing anyone to Saitama isn’t that fair so the Sea King is still really tough.

The Atomic Samurai is a cool operator who holds his pride close to his heart. When Saitama first tried to shake his hand, he refused, stating that he would only acknowledge him when he got into the higher ranks first. Despite that, he is not unkind. He has his own school of disciples who take after his unique techniques. One of his disciples, Iaian, becomes severely injured during the alien invasion and he shows a great deal of care and concern for him. Despite not being the highest on the list, the Atomic Samurai is nothing to scoff at. He uses a katana to dispatch most of his opponents with ease, not only boasting superior technique but all round better stats as well such as strength or reflexes. His signature technique, Atomic Slash, cuts the enemy into uncountable pieces in a single instant, leaving behind nothing but dust. When you meet him, don’t even blink, it’ll be over before you know it.

Bang is that one oldie that’s been around so long that he should have become old and frail, yet no one wants to mess with this guy. It’s partly due to his rank as number 4 on the S-rank list. However, it's most probably because of what a beast and badass Bang can be. Earning his moniker of Silver Fang, he darts around the battlefield decimating his foes with ease, his silver hair flashing all the while he is doing so. The Silver Fang utilises the style of Water Stream Rock Smashing Fist. It’s a relatively powerful fighting style that seems to take after forms of martial arts like Tai-chi, in which strength is not used but rather the strength of the opponent is turned against them. Despite this high level of technique, Bang possesses one of the strongest bodies in the entire series. With a technique that requires zero strength wielded by a guy who has plenty to spare, it is no surprise that he places so high on the list at all. Just don’t let him con you into being his disciple!

The older of two sisters, Tatsumaki received her moniker due in fact to the powers that she has received from being an Esper. Unlike the sissy levitations that normal psychics do like lifting a spoon or a small object, Tatsumaki lifts whole cities at a time to bombard the enemy with. The trail of destruction she often leaves behind has lent her the name of Tornado of Terror. She doesn’t just have power. When needed too, she could precisely fire rubble into the cannons of the enemy ship and cause them to backfire on their own crew. With the further use of her psychic abilities to boost her lack of physical ones, Tatsumaki is a strong contender for being one of the most powerful beings in the series.

Boros is an extraterrestrial being that has conquered so many planets and galaxies that he has begun having an existential crisis. He’s very bored. There seems to be nothing capable of challenging him anymore and he’s unhappy about that. One day, he receives a prophecy that there exists someone on Earth who can give him a fight of the centuries. Like every cliché villain ever, he gathers his armada and invades Earth. This is an alien so powerful, that his underlings are capable of giving S-rank heroes a hard time. And it shows. When faced against the strongest character of the series, instead of going down with one punch like everyone else, he actually takes multiple hits from Saitama before losing. In fact, this is the first time we see Saitama putting effort into fights, using his special techniques like the serious serious series. Lord Boros is the second strongest throughout the series so far purely for the fact that he managed so long against the Caped Baldy, after who else can boast of that fact?

Was this surprising? With his life going nowhere, Saitama decided to become a superhero so that he could save people after an incident in which he saved a child from a crab monster. 3 years later, after his “intensive” (read: 100 push-ups, 100 squats, 100 sit-ups, 10k marathon and no air-con) workout, he has lost all his hair and become immensely powerful, defeating anyone he comes across with one punch. Which loops back to him feeling like his life is going nowhere as he can’t feel the thrill of battle because everyone else is just too weak. Yet, despite his overwhelming strength, he doesn’t abuse it for his own need. With power like that, he could have easily taken over the world or led a decadent life, however, he lives like a NEET most of the time. He didn’t even take credit for defeating the Sea King, a feat only he could’ve done at that point of time, just so the other heroes wouldn’t be looked down upon. His greatest strength in all this is his heart and kindness. Well…not really. His greatest strength is…ONE PUNCH!