One of Marvel Comic’s greatest strengths is the shared universe the characters inhabit. Much like the Marvel Cinematic Universe, events from one comic book can impact events in another one, set in a totally different place with completely different characters.

But, every now and then, these characters are caught in situations which are simply too big for them to deal with alone and they form larger groups to end the crisis. Such an event was the catalyst for creating The Avengers in the first place.

Over the years, these crossovers have gone from small guest appearances to massive events where the entirety of the Marvel Universe is drawn into a single battle, often with far-reaching consequences.

Here are Marvel’s 15 Greatest Crossovers.

15. The Sin Eater

Daredevil and Spider Man In The Sin Eater Marvel’s 15 Greatest Comic Book Crossovers


Despite being a small crossover, The Sin Eater is a truly great story as it is a completely street-level entry. There’s no end of the world scenario, no overpowered villain, it’s just Spider-Man and Daredevil getting caught up in the same case and using some good old detective work to find their man.

The Sin Eater himself is later revealed to have previously worked for S.H.I.E.L.D and had been experimenting with various performance-enhancing drugs, driving him insane. He then set out to punish anyone he felt had sinned, including Spider-Man’s friend Jean DeWolff and Daredevil’s friend Judge Horace Rosenthal. With both costumed heroes on the case, it wasn’t long before they met up. It is in this story that Daredevil deduces Spider-Man’s secret identity and, despite coming to blows, the seeds for their eventual friendship are sown.

While The Sin Eater is a smaller crossover, it has ramifications to this day. The Death of Jean DeWolff remains a pivotal moment in Spider-Man’s life, with his anger and grief over the event frequently referenced. Also, it ties into the backstory of Eddie Brock, the first Venom, as his journalistic career was ruined by printing the ramblings of a serial confessor, pretending to be the real Sin Eater.

14. Siege

Sentry Ares Siege Marvel Marvel’s 15 Greatest Comic Book Crossovers


Siege was the final part of a storyline that started in Civil War and ran through Secret Invasion and Dark Reign. By this point, the various heroes of The Avengers and their closest allies had been fragmented by internal conflict, and usurped as the protectors of Earth by the Dark Avengers of Norman Osborn and his evil associates.

All that stands between Osborn and total control of Earth is Asgard. At this point in time, Asgard is floating above the Midwest, having been brought to Earth by Thor following Ragnarok. Osborn, along with the Dark Avengers and H.A.M.M.E.R launch a devastating attack on Asgard, killing everyone they encounter. Despite having no mandate, The Avengers and their allies the Young Avengers and Secret Warriors, led by a revived Captain America, head to Asgard to stand alongside their friends, and if necessary, die with them.

In the end, Osborn’s madness is exposed, causing the President to revoke H.A.M.M.E.R’s mandate as the world security force and ending the Dark Reign.

13. The Children’s Crusade

avengers childrens crusade Marvel’s 15 Greatest Comic Book Crossovers


Where Avengers Disassembled began Wanda Maximoff’s journey to madness, House of M cemented her as a major threat to not just the Avengers, but the whole world. The Children’s Crusade was the beginning of her redemption. It also managed to take away some of the blame for her actions as it was revealed that she wasn’t in total control of herself at the time of the attacks on the Avengers, or the decimation of Mutantkind.

The lost souls of Wanda’s sons, William and Thomas, had found their way into the bodies of Wiccan and Speed of the Young Avengers. These young men, and their companions, sought out Wanda along with their grandfather, Magneto, and their uncle, Quicksilver. With Wanda perceived as a threat, both the Avengers and X-Men were in hot pursuit of the errant youngsters.

While a satisfying story, The Children’s Crusade manages to resolve several plotlines as well as deliver some emotional punches, as well as set up some major storylines. The seeds of Avengers Vs X-Men, and the eventual fate of Wanda, all begin here.

12. Maximum Carnage

Maximum Carnage Marvel’s 15 Greatest Comic Book Crossovers


Maximum Carnage is everything that is right and wrong about the ‘90s. Excessively dark and violent, the storyline involved the maniac Cletus Cassidy A.K.A Carnage going on a massive murder-spree across Manhattan with his “family,” Shriek and the Spider-Doppelganger. Purely focused on chaos, Carnage has no master plan besides evoking fear among the population.

Of course, Spider-Man goes in pursuit but finds himself outmatched. Even siding with his sometimes-enemy Venom, he is unable to turn the tide of chaos. As the story evolves, and the body count increases, Iron Fist, Captain America, Deathlock, and others join the battle and eventually bring the city under control.

What makes Maximum Carnage stand out is the level of darkness in a Spider-Man storyline. While yes, it was the ‘90s, it was still a far more brutal story than usually seen in the adventures of the wall-crawler and set the tone for much of the next few years.

11. X-Tinction Agenda

x tinction agenda Marvel’s 15 Greatest Comic Book Crossovers


During the ‘80s the various X-books had gone from strength to strength, becoming Marvel’s flagship titles. But the characters themselves had become ever-more fragmented. Instead of all living happily under one roof, they had become scattered and directionless. While Forge and Banshee had set out to reunite the X-Men, they had yet to find several key members.

Taking a brief pit-stop at the mansion, the X-Men were sharing space with the New Mutants, who had recently come under the tutelage of the mysterious Cable, when Genoshian Magistrates attacked and kidnapped several New Mutants as well as a de-aged Storm.

Across the story, the X-Men teamed up with X-Factor (at the time the original five X-Men) as well as re-uniting with Wolverine and Psylocke, as well as Jubilee. Several key changes to the status quo happened, including Storm becoming her rightful age once more, Warlock’s death, and Havok’s freedom from his false life as a Magistrate. It also set up plots for the eventual Phalanx Covenant storyline. Action-packed, but with an emotional core, the X-Tinction Agenda remains one of the best X-Men stories ever.

10. X-Cutioners Song

13 Stryfe Marvel’s 15 Greatest Comic Book Crossovers


Possibly the definitive ‘90s X-Men storyline, the X-Cutioner’s Song had something for everyone. The X-Men were in a place of relative calm, despite several members having recently had emotional crisis. Colossus had just lost his brother, Cyclops had lost his son, and Wolverine lost the love of his life. Simultaneously, Xavier is the subject of an assassination attempt (thought to be by Cable, revealed to have been Stryfe) and Scott and Jean are abducted by the Horsemen of Apocalypse under the orders of Mister Sinister.

Pretty much every major player from the ‘90s got thrown into the mix, including X-Factor, X-Force, the Dark Riders, Bishop, Cable, and of course Wolverine. Numerous battles take place, friends are reunited, and plots are resolved. Much of the mystery of Cable and Stryfe’s origins begin to unravel, although the reader wouldn’t learn until later that Stryfe is Cable’s clone and not the other way around.

The story also sets up the major plot of the ‘90s, the Legacy Virus. When Stryfe is defeated, his contingency is unleashed, a pox on mutantkind, the ultimate antithesis of Xavier’s dream. While the Legacy Virus storyline would be mismanaged, leading to a massive anti-climax years later, the HIV/AIDS parallel to make people even more afraid of the Mutants was a clever allegory.

Arguably, the X-Men have never been better.

9. Secret Wars (The Original)

Secret Wars Marvel’s 15 Greatest Comic Book Crossovers


 

Back in the ‘80s, Marvel really needed to sell some toys as they had been flirting with bankruptcy for some time. Given the runaway success of the Star Wars and GI Joe toylines of the day, Marvel needed to shift some merchandise and needed a vehicle to sell them. The title of the story came from focus groups that learned that children responded positively to the words “Secret” and “Wars” and the story was reverse-engineered from there.

But, more than a mere vehicle to sell toys, the story became much more. All the major players in the Marvel Universe are brought to an alien world to do battle by the mysterious Beyonder. Simple stuff, but the story became much more than a series of fights. Stand out moments including The Hulk lifting a mountain, Magneto’s flirtation with Wasp, and Colossus’ flirtation with an alien native influenced their stories for some time. Of course, the biggest change in the status quo came when Spider-Man donned his black costume for the first time. Initially believing it to be an alien costume, he eventually learns that it is a sentient symbiote which would become the anti-hero Venom.

8. Avengers Vs X-Men

X Men Vs. Avengers Marvel Marvel’s 15 Greatest Comic Book Crossovers


On the surface, AvX is a simple battle between two teams of superhumans. But it’s much more than that, it is a battle between different ideologies. Captain America oversees the largest team of Avengers ever assembled and is determined to keep the world safe. Cyclops has been carrying the burden for the fate of his species for some time and is beginning to crack under the pressure. The two men each see the Phoenix Force coming and see it differently. Cap sees a foe to be vanquished, Cyclops sees the potential to save his race.

Each man is proved to be right in the end with the Phoenix responsible for untold destruction, but after finding its true host, Hope Summers, it revitalises the dormant mutant gene around the world.

The ramifications are still being felt in the Marvel Universe, and mutantkind is once again on the edge of extinction due to the M-Pox. Cyclops’ view that mutantkind may have to take a more aggressive stance to survive may yet be borne out.

7. Secret Invasion

The Skrulls from Marvel Comics Secret Invasion Marvel’s 15 Greatest Comic Book Crossovers


For quite some time, there was something wrong with the Marvel Universe. Nick Fury was missing, S.H.I.E.L.D seemed to be acting oddly, with the inexperienced Maria Hill having been put in his place. Several people seemed to have been maneuvered into positions of power and some of the heroes noticed that there was something off about the world.

Eventually, the New Avengers discovered that Elektra had been replaced with a Skrull capable of hiding from Wolverine’s hyper-senses as well as Doctor Strange’s magics. They quickly began to realize that anyone anywhere could be a Skrull, and distrusted both their allies and each other.

After a Skrull ship lands in the Savage Land, and simultaneous Skrulls attacks take place in key facilities across the world, the various heroes scramble to return to New York to fight the final battle against the Skrulls who believe themselves destined to take Earth for themselves after their own home world was destroyed.

Not only did the story feature almost the entire Marvel Universe was epic battles throughout, it also fed off themes of distrust. By the end of the story, the heroes were largely beaten despite their victory, and Norman Osborn was appointed the head of world security, ushering in his Dark Reign.

6. Infinity Gauntlet

Thanos False God Captain America Infinity Gauntlet Marvel’s 15 Greatest Comic Book Crossovers


The inspiration for the upcoming Infinity War movie, Infinity Gauntlet saw the cosmic terror Thanos achieve omnipotence. By combining the Infinity Gems into a single weapon, Thanos had the power to surpass even the combined powers of the various cosmic forces that hold the universe together. He had total mastery over life, death, time, and space.

With half the universe wiped out in an instant, the heroes of the Marvel Universe rushed to confront Thanos but were easily bested by the mad Titan. Eventually, he is only defeated by his own foolishness, pride, and arrogance, as well as a subconscious desire to fail as he knew he wasn’t worthy of omnipotence.

While a rip-roaring space opera The Infinity Gauntlet has laid the foundation for the inter-connected stories in the mega-successful Marvel Cinematic Universe. How many of the themes and events from the series will make it into the movie remain to be seen, but with only one Infinity Stone left to discover it won’t be long before we find out.

5. Civil War

Iron Man Punching Spider Man During Civil War Fight Marvel’s 15 Greatest Comic Book Crossovers


Much like 2016’s Captain America: Civil War, the comic book version begins with a tragedy. The town of Stamford is destroyed, including a packed school, when undisciplined young heroes attempted to bring down a team of villains, including the explosive Nitro.

In the wake of the disaster, The Superhuman Registration Act is brought in with the various heroes being required to work for the government or be forced to retire and have their powers removed. While Iron Man thinks this is necessary to avoid another disaster, Captain America believes that working for the government means that the heroes will be forced to follow people with agendas.

A series of brutal fights take place, heroes swap sides, heroes are shown to be undercover on both sides, and heroes fall in battle. What makes Civil War stand out is that there is no clear bad guy. It is an argument between two brothers in arms over how they see the world.

4. Avengers Disassembled

Ant Man Jack Of Hearts Avengers Disassembled Marvel’s 15 Greatest Comic Book Crossovers


Avengers Disassembled breathed new life into the Avengers franchise. While it did cross over the various Avengers titles, it was at its core a story about the broken heart of one Avenger, Wanda Maximoff a.k.a The Scarlet Witch. Having lost her sons, and her memory of them erased, her powers began to subconsciously attack those closest to her.

When she discovered the fate of her sons she broke down and her powers caused the deaths of some avengers as well as others to attack their friends and allies. By the time the crisis ends, Avengers Mansion is destroyed and the Avengers themselves are disbanded.

While the Avengers reassembled shortly after when the Raft prison break occurs, Avengers Disassembled set events into motion which as still being felt to this day. While most events claim that “nothing will be the same again” this one lived up to its promise. The decimation of mutantkind, the breaking of the Avengers, the Witch’s fall from grace, they all began here.

3. Onslaught

Onslaught X Men Professor X Magneto Marvel Comics Marvel’s 15 Greatest Comic Book Crossovers


 

While Charles Xavier had been shown to have a dark side before, nothing had prepared the X-Men for the Onslaught.

Months earlier, Xavier had been forced to enter the mind of Magneto and shut down his mind. In doing to a sliver of Magneto’s mind merged with Xavier’s unconsciousness and formed a personality of its own deep in the recesses of Xavier’s psychic brain. Over time this entity grew more powerful, and learned to operate without Xavier’s awareness.

Eventually, Onslaught became unleashed. Using a combination of Xavier’s mental powers, Magneto’s electromagnetic abilities as well as using X-Man as an unlimited source of psychic power, and Franklin Richards’ reality warping power, the Onslaught seemed unstoppable.

The Avengers, X-Men, Fantastic Four, even Doctor Doom stood against him and eventually hammer blows from the Hulk destroyed his physical form. This proved to have been part of Onslaught’s plan as his physical form was all that was holding him back from omnipotence. It was Thor, god of thunder, who attempted to merge with Onslaught to contain its power. His form wasn’t enough but with the Avengers and Fantastic Four also sacrificing themselves, Onslaught was defeated.

The Avengers and Fantastic Four were believed dead for some time, making life even harder for the mutants, and the ramifications were felt for several years.

2. House of M

Hawkeye erased House of M Marvel’s 15 Greatest Comic Book Crossovers


Essentially a direct sequel to Avengers Disassembled, House of M showed Wanda Maximoff struggling to control her body and mind while under the care of her father, Magneto. When the Avengers and X-Men meet to discuss Wanda’s powers, fearing a repeat of her lashing out once again, her brother Quicksilver encourages her to rewrite reality to give her the life she deserved, free from the Avengers and X-Men who would seek to end her.

The result was a universe-wide rewriting of history with only Wolverine and the mysterious child Layla Miller remembering the world as it was. Magneto is the ruler of the world and Mutants are the ruling class. While there are rebels, the world is essentially at peace. However, Wanda’s mind is still fractured and she cannot maintain control indefinitely. The heroes, thanks to Layla Miller, begin to rediscover themselves and form a team under the command of Cyclops who attempts to put the world back to the way it should be.

Despite their success, Wanda unleashes a spell which robs 90% of the world’s mutants of their powers and causes the world to fear her.

1. Age Of Apocalypse

Horsemen of Apocalypse Marvel Comics Age Of Apocalypse Marvel’s 15 Greatest Comic Book Crossovers


When the son of Xavier, the insane Legion, awoke from a coma he wished for a better world. A world where he could have had a normal life with his father. But his father had spent his life opposing Magneto so Legion sought to go back in time, kill a young Magneto and allow his father to raise him in a happy family. He botched the attempt and killed his father instead. With no Xavier, the history of the world turned out very differently and Apocalypse rose far sooner.

By the present day, Apocalypse has conquered America and much of the rest of the world is a wasteland. His only opposition is a team of X-Men (named in honour of the fallen Xavier) led by Magneto. These X-Men seek to undo Legion’s actions and make the world right again and take the battle to Apocalypse. Eventually, the world is restored but several mutants manage to cross over into the Marvel universe before the AOA falls.

The Age Of Apocalypse is essentially the perfect crossover event. Several characters have had totally different histories allowing for them to be seen completely differently. Some heroes are now evil villains, and some villains are now heroic. There are deaths, some deeply poignant, and some incredibly brutal. There is also hope. In the darkest moment in X-Men history, Xavier’s dream is kept alive by his best friend.

Despite being printed over 20 years ago, the AOA is still a significant chapter in Marvel history. Many aspects, including the timeline itself, have been revisited several times.