Superman is one of the biggest DC superheroes.
His Kryptonian DNA allows him the powers of super-speed, flight, super-strength and so much more. He is not just the champion of Earth, but arguably the entire cosmos. It's hard to think that Superman could ever lose, but it has happened before.
Many in the DC universe themselves gave him a run for his money. However, the Marvel universe is also filled with characters who are filled to the brim with power. Even if they don't match his strengths, they could be lethal in attacking his weaknesses.
The Man of Steel has many variants that are virtually unbeatable by any entity within the DC universe. For the sake of this article, we're talking about the New 52 Superman. He is by no means weak as he bench-pressed the weight of the entire Earth for 5 days.
However, he has all the weaknesses that Superman traditionally does. He is susceptible to attacks from magic users, spiritual entities, reality-warpers, energy manipulators, and psychological manipulation. In addition, he has seen defeat through the use of Kryptonite, as shown by Lex Luthor many times.
Here's a ranked list of 10 Marvel characters who could defeat Superman if it ever came to it.
Disclaimer: This article contains the author's opinion, which might vary from the opinions of the fans.
Scarlet Witch, Thor, and 8 other Marvel characters who can defeat Superman
Clark Kent is the closest being there to possessing godly strength without divine origins. Thus, it only makes sense for him to be defeated by those of an unnatural order of strength.
10) Scarlet Witch
Scarlet Witch has shown that she is capable of withstanding the greatest of Marvel contenders. In Doctor Strange in the Multiverse of Madness, Scarlet Witch more than proved that she could easily depower the Illuminati. A variant of Captain Marvel is also in the film, which Scarlet Witch takes down by absorbing her powers.
Wanda can do the same with Kal-El. Seeing that the Sun is the source of all his strength, it's only a matter of how she chooses to depower him. Even without her reality-bending powers, her chaotic magic works against him. With magic as his weakness, her attacks will more than damage him. Of course, the Kryptonian is no pushover, which is why taking control early on in the fight will decide which way it goes.
Thanos proved to be an exceptionally formidable foe in the MCU. Speaking outside the movies, however, Thanos is just plain fierce. Scaling with the power levels of Darkseid himself, the Mad Titan is also a genius tactician. Even if Superman comes at him with full force, Thanos might have something in store for him.
Superman certainly falls flat if Thanos is in possession of even one infinity stone. He would stand a chance if it was the All-Star Superman variant, who could lift up to 200 quintillion tons. However, he is unlikely to unleash himself given his moral code, which is where Thanos would prevail.
Hyperion is another copycat of Superman. Both have similar inceptions of coming to Earth from dying alien planets. However, a prominent version of Hyperion was raised by the U.S. government and grew up to be an operative. That gives him an edge over DC's Big Blue Boy Scout in giving it his all.
Both Superman and Hyperion are powered similarly. While the former gets his power from the sun, Hyperion relies on absorbing cosmic radiation. It only becomes a matter of who runs out of steam sooner. With conditions siding further with Hyperion, he could very well win against the Man of Steel.
Mephisto is an extremely powerful demon who has been a reality-ending threat many times in Marvel. He is everything Superman gets overpowered by, all packed in one.
Superman certainly has his own abilities which could help him control the situation in hand-to-hand combat. However, Mephisto has the power of energy absorption, teleportation, dimensional alteration, and necromancy, all of which are nightmarish for Superman to deal with.
Mephisto is immortal, while Superman can be killed. With his psychological powers, the former could mesmerize him, or even take his soul if Superman's will gives way. The odds would be entirely against him.
6) Captain Marvel
This is a tough sell, given how Captain Marvel does share the psychological weaknesses of the Good Samaritan. But in terms of both skill, strength, and endurance, neither will run out of steam any time soon.
The only way Captain Marvel can defeat the Man of Steel is by using energy absorption. Being a Kree-Human hybrid, Captain Marvel is a cosmic-level hero who has faced even more formidable odds. While Superman is truly the epitome of strength, it's over for him if Captain Marvel can figure out how to depower him.
The God of Thunder has taken on the Man of Steel before. During the JLA/Avengers #2 (2003), Kal-El and Thor faced each other in a fierce battle. The Kryptonian was on the losing side of things until he managed to lift Mjolnir and even caught it mid-air.
Kal-El won that fight. However, as the story nears its conclusion, Thor lets him know that it was Odin who allowed him to lift the hammer before, as he couldn't do it again. Thor was humble in accepting his defeat, as he knew that he wasn't even trying to win. The Man of Tomorrow even says that the Asgardian god is the strongest opponent he's faced thus far. If we were to get a rematch, we know how things would turn out.
4) Iron Man
Iron Man is a tactical and technological genius. Still, it wouldn't help if Superman would just run into him at lightspeed and obliterate him completely. Normally, that's how it would go, but this is where Iron Man's genius would shine.
We know what Lex Luthor and Batman are capable of with Kryptonite in their arsenals. Iron Man can use the same tactic if given the knowledge and make a suit that heavily incorporates kryptonite, as well as the powers of the Red Sun. With things that weaken him and turn him into a regular human, he doesn't stand a chance against Iron Man.
3) Doctor Strange
The Master of Mystic arts has many advantages over Superman. He's a tactical mastermind capable of altering reality. He's the strongest magic user there is. With magic as his natural weakness, the Man of Steel would have no choice but to face the hurt.
Doctor Strange has another great advantage. With Time Stone, he can simply evaluate the thousands of timelines where Kal-El loses, and use that knowledge to manufacture a lethal scenario that would break the Last Son of Krypton.
Galactus is as old as the universe in the Marvel comics. He is capable of shifting planets light-years away using telekinesis. Since he's imbued with Power Cosmic, dodging his attacks won't ever be a problem. Kal-El is very powerful, but he doesn't stand a chance against Galactus.
The only way he could ever have a chance is if Galactus is weak with hunger. He has taken the full force of Thor's Mjolnir without even noticing it, which just goes to show that Superman might prove to be nothing more than a nuance for the cosmic horror that is Galactus.
The son of Professor X, Legion is one of the most bizarre and powerful mutants to ever exist. Not only is he a natural reality-warper, but with his 200 Omega-level split personalities who have their own prowess over different abilities, the Boy Scout can only guess how he would lose.
In terms of strength, of course, the Man of Steel wins. But with Legion's reality warping, he could find himself in a completely different dimension by the time he's thrown a punch. Without warping, he could still win, as he can absolutely dismantle Kal-El's psyche.
The Man of Steel is without a doubt a force to be reckoned with. But even within DC, he's seen defeat at the hands of many. It's natural that there are beings in the Marvel universe who can take him down.
Sentry, Molecule Man, Gladiator, and Blue Marvel are all different adaptations of the Man of Steel concept. Then there are the Celestials and cosmic entities in the Marvel universe who are powerful beyond the scope of conception. If Superman mistakenly enters the Marvel universe without any backup, he might have a hard time surviving.