Comic book history is filled with massive crossover events that brought together some of the medium’s most recognizable heroes and villains. The 2000s were particularly notable in this regard, producing stories that pitted former allies against one another, introduced universe-threatening dangers, and permanently altered the status quo of Marvel and DC for years to come.

These events stood out not merely because of their enormous casts and destructive battles, but also because of the lasting consequences they left behind. They introduced new characters, reshaped major ones, created unexpected alliances, and in some cases, established brand new universes. This piece features some of the greatest event comics from a particularly memorable decade for superhero publishing.

8

House of M

House of M is a major Marvel event centered around the unstable Scarlet Witch and the full potential of her reality-altering powers. It follows the devastating events of Avengers Disassembled, where Wanda’s mental breakdown caused the deaths of several heroes and shattered the Avengers. From then on, she became increasingly unstable, with many believing drastic measures should be taken.

As a result, the Avengers and X-Men gathered to decide what to do with Wanda, making their way to Genosha to confront her. Before they could decide her fate, however, she transported everyone to an entirely different reality after Quicksilver influenced her. In this strange realm, Magneto ruled over a world where mutants occupied the highest position.

Wolverine was among the few characters who retained memories of the original reality and quickly realized something was wrong. He began searching for other heroes who could remember their lives before the transformation, eventually helping ignite a rebellion against Magneto. The conflict culminated in Wanda restoring reality, but her final act carried devastating consequences for mutantkind worldwide.

7

World War Hulk

World War Hulk is a Marvel event that followed the Hulk’s exile from Earth after the Illuminati had decided that his destructive nature made him too dangerous. He landed on the planet of Sakaar and managed to establish a stable life, which included a wife and unborn child. Unfortunately, his spaceship exploded and destroyed much of the planet soon after.

Leading Korg, Miek, Hiroim, and his other Warbound allies, Hulk arrived on Earth seeking revenge. He demanded that Iron Man, Mister Fantastic, and Doctor Strange face him, while several other heroes attempted to stop his advance. New York soon became the center of the conflict, witnessing unprecedented carnage and destruction.

Hulk defeats one opponent after another and ultimately captures some members of the Illuminati, forcing them into gladiatorial-style combat. He aims to fully humiliate them for their transgressions, but is halted by the arrival of The Sentry. Their battle pushes both titans to their limits, and Bruce Banner then emerges, along with the final twist of the tragic conflict.

6

Sinestro Corps War

The Sinestro Corps War centers around the return of Hal Jordan’s former mentor and one of the Green Lantern Corps’ greatest enemies, Sinestro. He formed his own army using yellow power rings and recruited some of the most feared beings in existence. His goal was to spread fear across the universe, and he waged war against the Green Lanterns.

The conflict began when the Sinestro Corps launched a devastating assault on Oa, catching the Green Lanterns off guard and freeing several dangerous prisoners. Kyle Rayner was also captured and manipulated into becoming the latest host of Parallax. Hal Jordan, John Stewart, and Guy Gardner were forced into a desperate rescue mission that took them into enemy territory.

The war eventually spread to Earth as well, involving many other notable heroes like Superman, Batman, and Wonder Woman. Besides Sinestro, they faced powerful opponents including the Anti-Monitor, Cyborg Superman, and Superboy-Prime, while the Guardians changed the Corps’ rules to permit lethal force. Though Sinestro was ultimately defeated, his campaign left the Lanterns forever changed.

5

Blackest Night

Following the events of Sinestro Corps War, another threat tied to the Green Lanterns plagued the DC Universe. Black Hand, a longtime enemy of Green Lantern, became the herald of Nekron, a powerful being connected with death. He gained control of black power rings and used them to raise the dead, creating an army of Black Lanterns across the universe.

The invasion soon reached Earth, where the newly created Black Lanterns took the forms of deceased heroes and loved ones. They attacked their former allies while exploiting the emotions stirred by their appearances. Hal Jordan and his fellow Green Lanterns were joined by other heroes, while the different Lantern Corps were forced to cooperate against the growing threat.

The Earth was soon revealed to be Nekron’s main target, as it housed the Entity of Life, the birthplace of all life in the universe. He sought to destroy the entity and thereby extinguish life itself. Hal Jordan served as the entity’s host to defeat Nekron, giving birth to the White Lanterns and overcoming the formidable threat.

4

Secret Invasion

Secret Invasion follows the Skrull Empire’s attempt to secretly conquer Earth. The shape-shifting aliens had infiltrated human society for years, replacing important heroes and other influential figures without being detected. At the center of the operation was Queen Veranke, who spent years disguised as Spider-Woman while preparing the planet for a full-scale Skrull takeover.

The conspiracy comes to light when the New Avengers discover that their enemy, Elektra, was actually a Skrull in disguise. Reed Richards examines the impostor and realizes the aliens have developed a way to hide from conventional detection. Soon after, Skrull infiltrators reveal themselves all over, leaving heroes unable to trust even their closest allies.

The Skrulls finally launch their open assault, bringing a massive armada and super-powered soldiers to Earth. Heroes from across the world unite to repel them, while Veranke leads the invasion from the front. Norman Osborn kills the Skrull Queen during the final battle, and the assault ends with the Marvel Universe entering an entirely new political era.

3

Annihilation

Annihilation centers around a devastating invasion led by Annihilus, ruler of the Negative Zone. He unleashes the Annihilation Wave into the positive matter universe, sending countless soldiers across the galaxy and destroying everything in their path. Xandar is among the first major targets, with its defenders overwhelmed as the invasion quickly reaches an unprecedented scale.

Richard Rider survives Xandar’s destruction and becomes the last surviving member of the Nova Corps. He bonds with the Xandarian Worldmind and gains access to the power of the entire Nova Force, dramatically increasing his strength. He later joins Drax, Star-Lord, Ronan the Accuser, Gamora, and several other survivors who form a resistance against Annihilus.

The resistance struggles to slow the invasion as Annihilus continues conquering world after world. The terrifying despot manages to control Galactus and uses him as a destructive weapon, until Drax and Silver Surfer help free him. Galactus then devastates the invading forces, allowing Nova to confront Annihilus directly and finally end the war.

2

Infinite Crisis

Infinite Crisis was a DC Comics event preceded by a series of disasters that left the universe deeply unstable. Batman had grown distrustful of the superhero community, Superman struggled with his waning confidence, and Wonder Woman faced the consequences of killing Maxwell Lord. Meanwhile, OMACs attacked heroes, magic deteriorated, and the Rann-Thanagar War threatened worlds across the galaxy.

The situation worsened when Superman of Earth-2, Alexander Luthor Jr., and Superboy-Prime returned from a hidden dimension. They had survived the original Crisis on Infinite Earths and believed the modern universe had lost its way. Alexander secretly exploited the heroes’ divisions while building a machine to restore the Multiverse to what he considered a better state.

His plan took shape as multiple Earths began reappearing and Superboy-Prime turned against the heroes. He murdered the younger Superboy, fought Superman, and helped devastate the DC Universe before the heroes finally destroyed Alexander’s machine. The Green Lantern Corps eventually defeated and imprisoned Superboy-Prime, though Luthor’s efforts resulted in the rebirth of the Multiverse.

1

Civil War

Civil War was one of Marvel’s most standout events, beginning with a seemingly run-of-the-mill battle between heroes and several supervillains. The scuffle, though, results in a massive explosion that kills hundreds, including many children. The tragedy turns public opinion against superhumans and pushes the government to pass the Superhuman Registration Act, forcing every costumed hero to make a tough decision.

The law requires superhumans to reveal their identities and work under government authority. Iron Man supports registration and begins organizing heroes who accept it, while Captain America rejects the measure and goes underground. The disagreement divides the Avengers, Fantastic Four, and other heroes, which ultimately brings them into their first major battle.

The conflict takes a darker turn when Iron Man and Mister Fantastic deploy a cloned version of Thor to the fight. The imposter kills Goliath, making the conflict increasingly violent and forcing several heroes to reconsider their positions. The war then reaches New York, where Captain America surrenders after seeing the destruction caused by their fight, ending the sprawling dispute.