The Justice League is a team of the greatest heroes the DC Universe has to offer and they have one of the most difficult missions around- to protect the creation from the most dangerous threats. The team has found itself fighting everything from alien invaders to supervillains to otherworldly gods and every time, they've managed to triumph, saving the day with their near unbeatable combination of power and know-how.
Over the years, the Justice League has faced down some truly dangerous foes, ones who have challenged them in all kinds of ways, pushing them to their limits, earning them their place as the most powerful group in the DC Universe.
10 Despero Is A Mental And Physical Titan
A despot from the planet Kalanor, Despero has changed a lot since the first time he battled the team. For years, his threat to them came from his vast telepathy and cunning but he would eventually become a dangerous physical challenge for the team as well. Able to battle the team to a standstill on his own, Despero is one of the League's most dangerous foes.
Despero can challenge the Justice League like few others- his telepathy is a challenge for Martian Manhunter, he's strong enough to fight Superman and smart enough to lay out plans that even Batman has trouble unraveling.
9 Starro the Conqueror Was The League's First Foe
Starro the Conqueror was the first villain the Justice League ever faced and one of its weirdest. The alien starfish attacked entire planets, using smaller versions of itself to enslave the inhabitants. It took a lot for the Justice League to defeat the alien and every time it's shown up since has been a harrowing ordeal for the team, one that has truly tested them.
Starro represents a different kind of threat than most- not one they can punch into submission. It takes all of the League's brains and brawn to defeat the massive starfish and stop it from encircling the Earth with its terrible arms.
8 Amazo Has All Of The League's Powers
Amazo is one of the deadliest androids in all of comics. Able to copy all of the powers of the Justice League, Amazo is limited by his AI but that doesn't stop him from being one of the greatest threats to the League. Any being that can be as strong as Superman, fast as the Flash, and create energy constructs like Green Lantern is going to be dangerous.
It takes everything the League has to defeat Amazo. While they know their powers like the back of hands, dealing with someone that can use all of them at once is a massive challenge, one the League has almost failed at.
7 The Legion Of Doom Is An Assemblage Of The Greatest Villains
The Legion of Doom is the inverse of the Justice League- an assemblage of the greatest villains on the face of the Earth. The League's most powerful foes make up the team and bring their expertise in battling their heroic enemies to every battle they fight. The Legion has proven to be a great threat to the League and give the heroes a tough time whenever they meet.
Recently, the two teams have been fighting each other often, as Lex Luthor tried to tip the balance of power to the concept of Doom and gain enormous power in the bargain. The Legion beat the League at nearly every turn, proving just how dangerous they could be.
6 The Crime Syndicate Are The League's Evil Doppelgangers
The Justice League has faced down the Crime Syndicate in one guise or another many times over the years. Hailing from Earth-3, the Crime Syndicate is the evil version of the Justice League, using their powers to subjugate their world and protect it from the threat of heroism. Much like the League, in their world, the Crime Syndicate always wins.
The two teams' battles have always been heated affairs, ones that the League has just barely survived. In one of their last encounters, the Crime Syndicate was able to defeat the heroes of the Earth and take over. The only thing that stopped them was a group of villains under Lex Luthor defeating the Syndicate.
5 The Batman Who Laughs Almost Recreated The Multiverse In His Own Twisted Image
In the last few years, the Batman Who Laughs has been everywhere. While there are many who thought the character was overexposed and overstayed his welcome, there's no denying how dangerous he was. The Batman of a world where he became infected with a Joker virus, the Batman Who Laughs was one of the most dangerous foes the League had faced in years.
A Batman with the non-existent morals and insanity of the Joker is one of the most frightening things anyone could imagine. In his mission to remake the Multiverse in his twisted image, he outsmarted nearly everyone he faced and proved to be one of the greatest threats the League had faced in years.
4 Mageddon Destroyed The Old Gods
Known as the Anti-Sun and Warbringer, Mageddon was a powerful machine created by the old gods in the war that led to their extinction eons ago. It destroyed the old world of the gods, an act that brought about New Genesis and Apokolips. It would return years later and target the Earth, using its power to engender rage in the minds of intelligent beings to get Lex Luthor and his Injustice Gang to attack the Watchtower, splitting the League's focus.
Mageddon was able to beat the League at every turn and almost destroy them until the team used a modified Purple Ray to give every human on Earth superpowers. Together, the people of Earth were able to defeat it.
3 Darkseid Is The God Of Evil
Darkseid is the God of Evil. As the lord of the planet Apokolips, Darkseid has at his disposal are legions of soldiers and their powerful commanders. The forces he can bring to bear against his foes are amazing but none of them are as dangerous as Darkseid himself. Titanically strong and with vast energy manipulating abilities, including the dreaded Omega Effect, there are few beings who can stand toe to toe with him.
Darkseid has battled the League on many occasions. They've been able to keep him from succeeding but they never truly defeat him, as he always comes back more powerful than before and ready to fight the battle all over again.
2 Perpetua Was The Mad Mother Of The Multiverse
Perpetua was one of the Hands, beings who create Multiverses. At some point, she decided to remake the Multiverse and the beings within into creatures that would challenge even the Hands. However, she was imprisoned in the Source Wall before she could put her plan into action. When the League broke the Wall to defeat Barbatos, she was able to escape and begin her quest anew.
First using Lex Luthor and the Legion of Doom and then the Batman Who Laughs, Perpetua was able to outmaneuver the League and almost succeeded in her quest. However, she underestimated the treachery and resources of the Batman Who Laughs and it cost her everything.
1 The Anti-Monitor Almost Destroyed Everything
The Anti-Monitor is the Multiverse's ultimate villain. While his mother Perpetua was more powerful, even she never was able to accomplish what the Anti-Monitor was able to. From his base in the Anti-Matter Universe, the Anti-Monitor was able to destroy a near-infinite number of worlds in the Multiverse, until there were only five left.
The Justice League themselves had no chance against the Anti-Monitor. It took all of the heroes of the five remaining Earths to defeat him and even then it was a close thing. He's reared his ugly head several times over the years and anytime he shows up, the heroes remember what fear truly is.