As a paragon of good, it's natural for Superman to have a vast array of dark reflections. Even Godzilla has a large number of evil(er) opposites, and the Man of Steel's been around a lot longer than the Atomic Dinosaur. Given Superman's flirtations with corruption in the Dark Multiverse, this is a great time to explore the character's many evil alternates.
These include a surprising number of DC characters, who can't get enough of the good guy turned bad, but also pastiches and copycats from other comics companies. Superman's evidently too good a character to not reimagine as evil, over and over again until the death of our yellow sun.
Earth-Prime's Superboy started out as a hero. However, after joining the multiversal effort to defeat the Anti-Monitor, he ended up joining several other Supermen and Alexander Luthor in a "Paradise Dimension." From there he was able to watch as time passed outside his universe, and things remained the same in his. This frustrated Superboy-Prime so much that he punched through reality and broke into his contemporary continuity. He constructed solar-powered armor based on the Anti-Monitor's, and then tried to make a perfect world via mass murder. Prime was much more powerful than current continuity characters, and was able to murder most local heroes pretty easily. This plan reached his climax when he joined the Sinestro Corps, becoming one of the Top 10 OP characters in DC history, and killed the Anti-Monitor a second time.
A Superman who murders worlds in the name of utopia, Superboy-Prime is easily one of the worst of the lot.
9 Hank Henshaw
Another murderous Superman is Hank Henshaw, the super-impostor in Terminator drag. Already an established villain, Henshaw used Doomsday's and Superman's apparent mutual destruction as an opportunity. Using his ability to infect machines with his consciousness he built a Kryptonian/cyborg body out of the Man of Steel's DNA and tried to ruin Superman's reputation via petty Armageddon when he and Mongol destroyed Coast City. Real Superman and company eventually defeated and discredited the so-called Man of Tomorrow, but he's been a resilient villain. He even joined Superboy-Prime in the Sinestro Corps, which ended badly for him when Primey used him as a weapon against the Anti-Monitor.
8 King Hyperion
The Squadron Supreme is Marvel's version of the Justice League, sporting heroes like The Whizzer and Power Princess. When the team premiered in 1969, though, they were the Squadron Sinister, the living embodiment of the desire to see The Avengers punch Batman. Thor's opposite in this match-up was Hyperion, whom he used Mjolnir's magic to entomb inside an atom-- neat! Good and bad versions of the character have thrived in comics since, but even in the worlds where a good Hyperion is supposed to dominate, the baddie is always lurking in the wings. The character's most recent iteration was Secret Wars' King Hyperion, the dictatorial ruler of the Squadron's Battleworld domain who later infiltrated The Thunderbolts. His Atomic Vision and vulnerability to Argonite make Hyperion a shameless knock-off, but we love him.
7 Injustice Superman
Injustice may be a derivative video game commercial, but it delivered an evil Superman. In a storyline amalgamated from diverse comics plots along with the Justice League animated two-parter "A Better World," the Joker sadistically fear-gasses Superman into killing Lois Lane. Superman responds by putting his open hand through the clown's chest and turns the world into a dictatorial police state. In the process, he doxxes Batman, murders Shazam and Martian Manhunter, converts the Justice League into his personal secret police, and gets his butt kicked by Alfred Pennyworth. He's finally defeated by a still-good Superman from another universe who encases him in a Red Sunlight generating capsule.
It's epic, and the idea of a totalitarian Superman is compelling, even if it feels like something DC fans have seen before.
Superdoom is more than just a Doomsday/Superman amalgam. He's a toxic idea. The Louis Lane and Jimmy Olsen of Earth-45 were researchers who mad scienced a tulpa-- a living thought-- into existence. They called it 'Superman,' an idea made to save the world. When they sold their technology to Overcorp, though, the company changed the design. The resulting "killer franchise" conquered his planet, and then invaded other realities to destroy the competition other Supermen represented. He killed his counterpart on countless worlds, until he met the Obama-inspired President Superman of Earth-23. Superdoom radiated such overpowering evil that even that world's white supremacist Lex Luthor allied himself with Calvin Ellis in stranding the beast in between universes.
5 Lex Luthor
Lex Luthor is the quintessential brains vs Superman's brawn. However, after Doomsday killed Superman in DC's Rebirth, Lex seizes the opportunity to don powered armor, engrave a glowing electric 'S' on the front, and proclaim himself the new Superman. He even joined the Justice League for a time.
It can be argued that, at least for this moment, Luthor wasn't evil. He was a brilliant egomaniac who thought he was the only one who could save the world. Not automatically evil, but certainly on the wrong path. Lex's run as Superman was marred with failures, moral and technological. His selfish drives put him in conflict with Superwoman, China's New-Superman, and of course, the replacement Superman who inevitably showed up. Luthor's motives weren't pure, but it was an interesting case of a bad person trying to do a good thing.
Superman's evil opposite from Earth-3 has a lot in common with King Hyperion. He's a brutal authoritarian and ruthlessly rules his version of the JLA, the Crime Syndicate. The character dates back to 1964 and has gone through many iterations. He was originally an alien who got his powers from Kryptonite, but he's also been imagined as an astronaut from Earth who was given powers by aliens. Trapped in a toxic love triangle with Superwoman, his Earth's Lois Lane, and Batman-analog Owlman, Ultraman's a perfect example of someone who has all the power but isn't happy. Hailing from an Earth where evil always wins, Ultraman is always looking for something new to conquer, torment, or both.
The first significant "bad" Superman, Bizarro dates back to 1958. He isn't always presented as evil. As Superman's "imperfect duplicate," he's often seen as confused, insane, or simply stupid. Bizarro's logic and understanding of the world are inverted, as is his morality. This doesn't stop him from doing a lot of harm. Sometimes he rescues people incompetently, endangering or ending lives by trying to emulate Superman. He's easily manipulated as well, and can be tricked into killing someone just by calling them his "best friend."
Few characters are purely good or evil. Bizarro's at least an agent of chaos, and sometimes he's just a murderer.
2 Kid Miracleman
The original Captain Marvel was both a reinvention and a rip-off of Superman. Marvelman, known in the States as Miracleman, was the British rip-off of Captain Marvel. When Alan Moore did a grittily rebooted character in the early 80s, he brought one of the hero's original allies back as a villain. Inspired by Captain Marvel's opposite number Black Adam, this grown-up version of Johnny Bates was the stuff of nightmares. He'd grown up as his world's only superman. He kept his powers a secret but used them to fulfill every nasty desire. Initially defeated by Captain Marvel, Junior's weakness-- he can't say his own name-- when he returned he artfully slaughtered the population of London to get Miracleman's attention and generated an eternal Bates cult.
1 Lord Superman
The alternate Superman from the aforementioned Justice League episode "A Better World," this Superman lost his way in conflict with President Lex Luthor. Luthor executed the Flash and mocked the Man of Steel for never being able to see things through to their logical conclusion. Superman executed Luthor with his heat vision, took over the world with his League's help, and formed the Justice Lords' crime-free regime. Their evil was insidious. They saw themselves as the world's saviors, and the terror and lobotomies necessary to realize their vision as a small price to pay. Of course, when they found an alternate Earth, they immediately imagined all the "good" they could do there.
As always, evil that mouths idealism is the most dangerous kind.