As befitting one of the most powerful figures in any form of fiction, Superman has to deal with some of the most powerful enemies in his comics. The hero has gone up against a wide range of villains, including everything from brilliant inventors like Lex Luthor, alien menaces such as Brainiac and cosmic figures like Mongul. But his most powerful foes are capable of breaking worlds and outright defying the laws of reality.
While the Man of Steel has been criticized for being too strong or powerful, Superman still has a few foes who are even stronger than him. Now, we're taking a look back at these major threats from Superman's rogues gallery.
Doomsday
Doomsday was introduced in the titanic "Death of Superman," where he served as the one threat that finally proved capable of putting down Superman (at least for a while.) Created by Dan Jurgens, The original version of the character was the result of years of scientific research, and was the result of efforts to create a form of life that could survive anything. Every time one of the creatures was killed, it would be reborn. But each time, it retained resistance to those methods. It also remembered each time it was killed, fueling its internal rage and making it more devastating. Every version of Doomsday is a monstrous brawler above all else, driven to kill whatever he can.
Doomsday is an almost unstoppable physical threat. He's capable of healing from almost any injury, which gives him enough strength and endurance to stand toe-to-toe with Superman. Beyond that, once he's been defeated in a specific manner, he becomes impervious to that form of attack going forward. It forces the heroes who try to contend with Doomsday to be creative in their methods. His greatest weakness though is overall lack of mental capacity, with Doomsday serving more as a physical threat.
Darkseid
As one of the New Gods, Darkseid rules over the dark world Apokolips. Created by Jack Kirby, this cosmic pantheon of characters are among the most powerful figures in the DC Universe. Darkseid is even on a greater level than the other New Gods, essentially serving as the God of Evil across the universe. The character has grown into one of the definitive villains of the entire DC Universe, but he has a particular hatred for the Man of Steel. Superman represents a pure sense of hope that he wants to influence, something that's antithetical to everything at the core of Darkseid.
Darkseid has enough endurance to survive almost any type of attack. He also has a host of powers, with his most devastating being his Omega Beams. The energy blast can disintegrate anything it hits, trapping whoever it strikes a series of endless terrible alternate realities. Darkseid is strong enough to force entire Justice League teams together to stop him. But even though he's almost unstoppable, he can be overwhelmed and (temporarily) destroyed. He'll eventually be capable of creating a new form, but can be stopped for periods of time with enough power.
Imperiex
Created by Jeph Loeb and Ian Churchill, Imperiex is the embodiment of entropy, a physical manifestation of cosmic energy who always seeks to end existence. He's spent all of time destroying and recreating the universe. He sends drones that contain just a fraction of his power to scout the galaxy. These avatars are capable of destroying entire galaxies with relative ease by themselves. Eventually, they end up targeting Earth, as the source of Crisis on Infinite Earths and the center of the reality as a result.
One of these avatars was strong enough to take on Superman alone. Superman was always forced to work with others to help combat the force, however, proving just how resilient and powerful Imperiex can be. Even that paled in comparison to what Imperiex-Prime was capable of, coming across almost as the DC equivalent of Galactus. t takes most of the DC Universe working together to contend with Imperiex when he attacked Earth, and he's ultimately defeated by being sent back to the Big Bang, where even Imperiex is overwhelmed by the sheer scope of power present.
Mr. Mxyzptlk
While the other threats that come after Superman pose physical dangers, none of them offer as much of an overarching threat as Mr. Mxyzptlk. Seemingly a playful imp from the 5th dimension, Mxyzptlk has the ability to teleport around in the mainline DC world and is incapable of dying by any basic means. As a being from another dimension, he's not constrained by any of the laws of reality. He can even manipulate the basic building blocks of reality around people like Superman.
Of all of his villains, Mxyzptlk is the one that potentially gives Superman the most trouble. There's almost nothing that Superman can to actually to do confront him on a physical level. Rather, Mxyzptlk is so powerful that Superman has to always find a way to out-think him instead of outright defeating him. The only real way to combat Mxyzptlk and stop his rampages is to trick him back into his own reality by forcing him to say his own name backward.
The horrifying potential of the character is rarely realized, but it was notably done in Alan Moore and Curt Swan's "Whatever Happened To The Man Of Tomorrow?" That version is more than capable of going all-out and requiring Superman to finally break his code against killing to stop him by tearing him out of reality thanks to the Phantom Zone projector.