The Justice League are DC's ultimate superteam, consisting of the greatest heroes on the planet and beyond. The team came together to face down the greatest threats in the Multiverse and has won every time, putting their powers and skills to the test. The Justice League has had a difficult job over the years and sometimes, that's caused the heroes to snap and use their powers in ways that aren't exactly the most heroic.
Plenty of members of the Justice League have used their powers in villainous ways in a variety of stories, whether they be mainline DC stories or in alternate universes.
10 DC Loves To Play The Evil Superman Card Whenever Possible
Superman is DC's greatest role model but the publisher often likes to ask the question what if he wasn't. So, while he's mostly a paragon of virtue in the main DC Universe, sometimes pushing the limit or getting mind-controlled into doing like evil, like when Maxwell Lord tried to get him to kill Batman repeatedly in Superman/Wonder Woman: Sacrifice, it's mostly on alternate Earths where he does the killing.
Injustice sees him go crazy after he accidentally kills Lois Lane. Kal-El of Earth-10 is a Nazi superhero called Overman. There are plenty of Elseworlds stories that feature an evil Superman as well. It's become a common, if a little played out, trope in DC.
9 Batman Once Took Venom
Batman faces down some of the dangerous villains in Gotham and it's not exactly easy. He was eventually introduced to the drug Venom, a steroid that gave him super strength but was horribly addictive. This was before Bane came along, but Batman turning to a super steroid to get an advantage over his foes is pretty villainous in a lot of ways.
To begin with, it was named Venom. Very few things in life named Venom are good for a person but Batman saw that and still did it? The drug affected him adversely psychologically beyond even the addiction but he was able to break its hold over him.
8 Maxwell Lord Used His Mind Controlling Powers A Lot
One could argue that Maxwell Lord's mental manipulations don't count, since the worst ones he did was after his time in the Justice League. The thing is he also did do it during his time with the JLI and mind control, even when used for good, is a slippery slope. Taking away someone's free will and making them do what one wants is pretty wrong regardless of the reasoning.
The fact that Lord would later his powers on heroes to take control of them and make them do his bidding shows that any sense of morality he had was pretty non-existent anyway, which renders the argument for the altruism of his actions moot.
7 Cyborg Takes Control Of Computer Systems All The Time
Usually, tech-themed villains like to do the whole "take over the government computers and get control of the nuclear arsenal" thing. It's pretty much synonymous with villains taking control of computers for their own purposes. Well, villains and Cyborg. Once he was made a League member and given new Mother Box-based powers, Cyborg taking control of computer systems was a big part of his utility to the team.
While he didn't use them like a villain would, just the fact that was using this ability that villains always use to take the world hostage shows a disregard for the security of other systems besides his own.
6 John Constantine Has Used A Lot Of Dark Magic
John Constantine has been one of the world's foremost mystical defenders for a long time, a man who will do whatever it takes to save the world from the forces of eldritch evil. Unfortunately, this has sometimes meant that Constantine has had to fight fire with fire and used magic that most would consider quite dark.
While he did what he could to not do this during his time with the Justice League Dark, it wasn't always possible. That doesn't erase all the times he did use dark magic over the years but at least he mostly didn't do it as a member of the League.
5 Zatanna Mindwiped Friend And Foe Alike
Mindwipes are one of those things that many telepathic heroes have used but that doesn't make them good. Destroying a person's mind is the last resort, a desperate move that isn't something anyone wants to do. It's not heroic; it's terrible. Zatanna's had to do a lot of horrible things in her years fighting evil but the worst were the mindwipes she committed as a member of the Justice League.
While it's not known if they're still canon, the fact that Zatanna, that sweet and heroic superhero sorceress, wiped the minds of villains and Batman was a shock to readers, one that many still haven't got over.
4 Martian Manhunter Has Used His Shapeshifting And Telepathy In Shady Ways
Shapeshifting and telepathy are powers that heroes and villains alike share but there's something inherently dishonest about both of them. A shapeshifter transforms into someone else in order to trick others; the most well-known shapeshifters are usually villains. Telepathy involves invading the one place where no one usually can, the mind.
Martian Manhunter has both of these powers and has used them for good but he's also used them to fool others. Both powers represent a slippery slope for heroes and Martian Manhunter has used them in the same method as villains have.
3 Black Adam Has Killed A Lot People With His Powers
Black Adam has been on a long journey to becoming a hero and that journey is littered with the bodies of those he's killed. Black Adam's first stint as a hero thousands of years ago was a different time, where killing was more acceptable. His times as a hero in the modern age are quite different but that didn't stop him.
Black Adam has committed a lot of murders with his powers, killing many foes. Sometimes, it was warranted and other times, it was done just because that was the way he did things. While he hasn't killed anyone while with the League, that doesn't change the fact of what he's done for years.
2 Barry Allen Changed Time For His Own Purposes
Time travel is something that both heroes and villains do, but it's why they do it that makes it heroic or villainous. Heroes travel in time to fix things that went wrong because of villains; villains do it to get their way. This makes Barry Allen's actions in Flashpoint completely villainous.
Sure, Barry went back in time to save his mother's life but that action caused a world that was objectively worse than the one before. Barry was the villain of the story and had to go back in time to stop himself from saving his mother, which finally made him the hero. It doesn't change the fact that many millions died because of his actions, even if they were wiped from existence.
1 Hal Jordan Destroyed The Green Lantern Corps And Became Parallax
Hal Jordan hasn't always been a model hero but his reaction to the destruction of Coast City showed how bad he could be. He ended up killing the entire Green Lantern Corps, destroying the Guardians of the Universe, and becoming Parallax. He'd try to reboot the DC Universe and create an all-new Multiverse, something his friends were able to stop.
Hal Jordan used his powers just as his foe Sinestro once did, disregarding his oath and trying to get his own way. He committed terrible acts and while it was revealed they weren't completely his fault, it doesn't change the severity or the facts of what he did.