Marvel's heroes have won some resounding victories over the years. They've stopped Galactus from destroying Earth, batted Thanos, and prevented multiple terrible futures. Even when their victories cost them something dear, many Marvel heroes believed the sacrifice was worth it. However, that can't be said for every win the heroes has amassed.
Marvel's greatest heroes are no strangers to winning, but sometimes the results are so severe, one questions whether the victory was worth the cost. Sometimes these heroes are haunted by the fact that their efforts barely changed anything. Sometimes, the aftermath leads to a new but unfavorable status quo. For Marvel's heroes, there's no outcome more bitter than realizing things have gotten worse after the smoke clears.
10 The Age Of Apocalypse
The Age Of Apocalypse represents Marvel's best multiverse story, a thrilling epic that remains a fan favorite. The final battle against Apocalypse and the mission to make sure this dark timeline never occurred ended with severe casualties. A nuclear attack devastated New York City and destroyed the survivors before the timeline could be restored.
Then the sequels happened. It was revealed that Magneto had saved most of New York, but the war started all over again. Things worsened when Weapon X became the new Apocalypse, dooming the alternate universe to more pain.
9 Days Of Future Past
Days of Future Past, by writer Chris Claremont and artist John Byrne, revealed the dark fate in store for the X-Men and the world if Mystique had assassinated Senator Robert Kelly. The future X-Men sacrificed themselves so Kate Pryde could go back in time and warn the X-Men of the present day. The team stopped the assassination.
However, Days of Future Present revealed that this dark future still took place. On top of that, the X-Men's futures were always inundated with Sentinels and the massacre of the mutant race. Despite the X-Men's efforts to stop it, Days of Future Past feels inevitable at this point.
8 Inhumans Vs. X-Men
Inhumans Vs. X-Men, by writers Charles Soule and Jeff Lemire and artist Leinil Yu, set the Inhumans and X-Men against each other, the fate of both races in the balance. The X-Men drew first blood, but the Inhumans struck back. However, the whole thing was a ploy for Emma Frost to destroy the Inhumans using reprogrammed Sentinels.
Queen Medusa ended up destroying the remaining Terrigen Mist cloud, dooming her race but saving mutantkind. The X-Men didn't fare much better, since they were the instigators of the conflict. No one came out of this conflict looking like winners.
7 Planet Hulk
The Hulk is great in a fight, as the rebels of Sakaar found out. In Planet Hulk, by writer Greg Pak and artists Carlos Pagulayan and Aaron Lopresti, a weakened Hulk found himself on the planet after being launched into space by the Illuminati. Captured by the Red King, he became a gladiator, but finally broke free after a battle with a brainwashed Silver Surfer.
Hulk became the rebels' greatest fighter, and the Red King was destroyed. Hulk and the rebels created an entirely new world on the planet, but it would all be for naught. Miek, one of Hulk's friends, despairing of the peaceful life, detonated the warp core of Hulk's ship. The planet was destroyed, Hulk blamed the Illuminati, and he and the survivors went to Earth for revenge.
6 Secret War (1985)
Plot armor saves the Avengers often. The team has to win, which is why the battle in Secret War (1985), by writer Jim Shooter and artist Mike Zeck, was never in doubt. The Avengers, along with the Fantastic Four, X-Men, Magneto, Hulk, and a few others were kidnapped by the One from Beyond. To claim the ultimate prize, they had to battle their greatest foes.
Doctor Doom stole the One from Beyond's power, but the heroes were able to beat him. After the battle, they were transported back to Earth, with no prize to speak of. The One from Beyond later returned to Earth as the Beyonder and wreaked havoc. Nothing was gained, despite all the pain the heroes had gone through.
5 Civil War II
Civil War II is a low point for 2010s Marvel. Written by Brian Michael Bendis with art by David Marquez, the story revolved around a conflict over the precognitive Inhuman Ulysses. Captain Marvel wanted to use him to stop evil before it struck, and Iron Man didn't want to do that. Sides were taken, Hulk got killed, and a giant battle took Iron Man out of commission.
Captain Marvel didn't even win anything, either. The Inhuman Ulysses ended up leaving Earth to join the cosmic beings of the universe. Hulk was dead, Iron Man was taken off the table, and Captain Marvel looked terrible. On top of that, Captain America, then a member of Hydra, used the situation to take more power for himself.
4 Civil War
Marvel doesn't always make good writing decisions. Civil War, by writer Mark Millar and artist Steve McNiven, has multiple examples of mis-characterized characters and a plot that put the heroes of the Marvel Universe at each other's throats. Captain America and Iron Man's war over the Superhero Registration Act drew in the heroic community and ended in a massive battle.
Captain America surrendered when he realized the damage that was being done, and a victorious Iron Man became Director of SHIELD. Cap ended up dead, killed by a mind controlled Sharon Carter. Iron Man became hated by the alums of Cap's side, and the weakened hero community was easy pickings for the Skrulls secretly placed throughout the SHIELD, the Avengers, and beyond.
3 Avengers (Vol. 4) #12.1
In Avengers (Vol. 4) #12.1 (by Brian Michael Bendis, Bryan Hitch, Paul Neary, Paul Mounts, and Cory Petit), Abigail Brand of SWORD asked the Avengers for help finding Spider-Woman. Spider-Woman had been taken by the Intelligencia while on a SWORD mission. The Avengers found her and defeated the Intelligencia, but the whole thing ended in disaster.
The Intelligencia unknowingly had Ultron in their custody, and he awakened during the battle. As the Avengers mobilized to attack him, Ultron retreated, in order to come back and win when he was stronger. While the Avengers saved Spider-Woman, their actions resulted in Ultron reviving. The villainous robot later crushed humanity in Age of Ultron.
2 World War Hulk
The Hulk is the strongest one there is, which was a problem when Hulk got back to Earth after the destruction of Sakaar. World War Hulk, by writer Greg Pak and artist John Romita Jr., featured the Green Goliath returning to Earth and smashing the heroes of New York City. Hulk desired revenge on the Illuminati, unaware that the Illuminati hadn't caused Sakaar's destruction.
Hulk ended up losing, but it's hard to say he was totally wrong. The Illuminati had done a lot of bad things, and Hulk was mostly right to attack them. At the end of the battle, nothing really changed and everyone suffered, but Hulk most of all, as he learned about Miek's betrayal and was beaten by his foes. Though the Illuminati had won the day, their victory kept them in power, which would have consequences in several future events.
1 Secret Invasion
Secret Invasion was a game changer. Written by Brian Michael Bendis with art by Leinil Yu, the story saw the Skrulls attack when the Avengers were at their lowest ebb. The New Avengers and Mighty Avengers were busy battling each other in the Savage Land. As the Thunderbolts under Norman Osborn, the Young Avengers, and Nick Fury's Secret Warriors fought the invasion, the Avengers barely survived the Skrull's trap.
During the final battle, Norman Osborn killed the Skrull queen Veranke with the world watching. Iron Man took a massive share of the blame, since he hadn't noticed the Skrull's infiltration of SHIELD. Thanks to his public victory, Osborn took over the Avengers and staffed the team with villains, beginning his Dark Reign.