There is something special about being an Avenger. It creates a sense of belonging, purpose, and camaraderie. Even criminals who briefly served on their rosters commented on the feeling that being connected to such a valiant group of heroes brings. The Avengers are far more than a team protecting the world -- they’re a family and no matter how brief a hero’s time is on that roster, that connection never goes away. Once an Avenger, always an Avenger, as the saying goes. That’s the idea, anyway, but anyone who’s picked up an issue of the Avengers or seen the movies knows that’s rarely the case. Earth’s Mightiest Heroes have always been prone to fighting in the ranks. Occasionally, they've even stabbed each other in the back.
Betrayal and vengeance in the Avengers are almost as old as the team itself. Their first case of a disgruntled team member (or an X-team member) happened only three issues into the original Avengers comics, and it certainly didn’t stop there. There are scores of double-crossings and back-stabbings in the Avenger’s history, and it’s not always someone we’d expect. Sure, sometimes it’s obvious: the hot-head, the grief-stricken, or the unstable one of the bunch, but other times? Well, it’s the faithful, the gentle, or the one beyond reproach. Sometimes, it’s the new guy or the guy who left the team a year ago and sometimes it's a founder, a senior member, or even the current chairperson. Here are just a handful of some of the Avengers who betrayed their team over the years.
20 BLACK WIDOW
While Black Widow is typically loyal to her friends, she's also prepared to cross them if need be. During Black Widow Vol 6, the Weeping Lion blackmailed Natasha and forced her to defect from S.H.I.E.L.D. On her quest to find the blackmailer and clear her name, Tony Stark tracked her down and took her back to Avengers Tower.
Things were headed in a classic team-up-to-save-the-day pattern when Natasha knocked Stark out and stole some of his equipment for her op. Everything up to that point, even letting Stark find her in the first place, had been to gain access to his facility.
19 HANK PYM
Hank Pym wasn't in a good place during Avengers #213. He was facing an Avengers court martial for his behavior in battle, and he was on the verge of a nervous breakdown. Desperate to keep his status as an Avenger, he built a robot with a weak point hidden in the design.
Pym planned to have the robot attack during the trial so he could easily defeat it and impress the other Avengers. When his wife and fellow Avenger Wasp advised against his plans, he did the unthinkable and then he demanded that she kept quiet. The Avengers learned the truth when the robot attacked, and Pym lost his status as an Avenger.
During "Secret Empire," Scott Lang naturally sided with the heroes and was a dedicated member of the Underground. At least, he was until Hydra took his daughter Cassie. After Hydra had his daughter, they forced him to report on the resistance's movements.
One of the more costly consequences of this was that he alerted Hydra when the heroes managed to find two fragments from the Cosmic Cube, and Hydra showed up at the Underground's doorstep. To Lang's credit, he did confess his involvement with Hydra and tried to make amends. He also played a critical role in restoring Steve Rogers when the Cosmic Cube reformed.
17 SCARLET WITCH
It's hard to blame Wanda Maximoff for wanting children. Since that was impossible with an android husband, she used her reality-warping powers to make it possible. But because the children were willed into being, they weren't actually real, and this eventually drove the Scarlet Witch insane. With her reality-bending power, she conjured up scenarios that tore the Avengers apart in the "Avengers Disassembled" story arc.
Iron Man gave a drunken speech at the UN that cost the Avengers their charter. She-Hulk ripped the Vision in half. A Kree warship materialized out of thin air and Hawkeye died stopping it. By the time they finally stopped Scarlet Witch, the Avengers were so broken that they temporality disbanded.
16 IRON MAN
Criminal and traitor aren't the first words that come to mind about Iron Man, unless we're talking about "The Crossing" story arc. As the story goes, Kang the Conqueror had slowly been corrupting Stark's mind, bending his will and driving him insane. To keep his secret from the team he had to end an Avenger, end an Avenger's affiliate, and then frame Hawkeye for the crimes.
When the Avengers found out, they went back in time to recruit a younger Tony Stark to stop the corrupted one. Even with the teenage Iron Man's help, the corrupted Tony Stark and Kang nearly destroyed time as we know it.
Namor was never what we'd call a "model Avenger". He clashed with nearly everyone on his team and disregarded most of their rules, and considering he lost his wife during his time as an Avenger, it wasn't the happiest experience all around. After he left Earth's Mightiest Heroes, he joined the X-Men and sided with them during the Avengers Vs. X-Men series.
The X-Men decided they would try to capture the Avengers, but Namor had a more drastic plan in mind. He traveled to where the Avengers hid in Wakanda and tried to drown them all with a giant wave. The Avengers survived, but the massive wave devastated Wakanda and caused a long rivalry between Sub-Mariner and Black Panther.
14 BLACK WIDOW (ULTIMATES)
Not to be outdone by her prime universe counterpart, the Black Widow from the ultimate universe had a far more vicious double cross. In the Ultimates 2, Romanova was none too happy with her universes equivalent of Avengers, the Ultimates, or the country they fought for. She claimed that America had made Russia "a bankrupt nation of hookers and gangster."
In retaliation, she helped Loki's group the Liberators invade America. During her quest for revenge, she also leaked information about the Hulk to the press, framed Captain America for the demise of Hawkeye's family, took out Jarvis, and tried to steal Tony Stark's fortune.
Jacques Duquesne wasn't the ideal Avengers candidate. He tried to join their ranks to further his criminal exploits but was quickly turned down. Later in Avengers #20, he teamed up with the Mandarin to infiltrate their ranks and exact revenge. The Mandarin used a hologram of Iron Man to convince the Avengers to accept the Swordsman, and in exchange, the Swordsman planted a bomb in Avengers Mansion.
During his time as an Avenger though, Swordsman developed feelings for the Scarlet Witch and tried to dismantle the bomb to save her. The Avengers caught him with the bomb and branded him a traitor, although he would later rejoin the Avengers as a hero and win their trust.
Vision isn't one to betray his team, at least, not unless there is a perfectly logical reason for it. After he linked up with a supercomputer from Titan, Vision began to believe the only way he could protect Earth was to run it.
At first, he only wanted some additional power, and he helped Hawkeye establish the West Coast Avengers to expand the Avengers influence and even met with the leader of the free world about making the leader of the Avengers a cabinet position. When his schemes didn't give him the control he wanted in Avengers #253, he took over nearly every computer on the planet, starting with the machines that controlled the world's weapons.
99.99% of the time, Edwin Jarvis is the Avenger's faithful butler and dependable ally. In addition to running Avengers headquarters, he often went on monitor duty or manned communications while the Avengers were out. On one occasion, however, Jarvis actually helped Ultron-5 capture Earth's Mightiest Heroes.
Avengers #54-55 details how Jarvis sold Ultron-5 (disguised as the Crimson Cowell) plans of the Avengers HQ to help stage an attack. Initially, Jarvis told the Avengers that he needed the money to help his sick mother. Months later though, he learned that Ultron-5 had actually hypnotized him before he gave up the plans.
10 WONDER MAN
When Simon Williams first joined the Avengers, his life depended on betraying them. Wonder Man acquired his powers from Baron Zemo and the Masters of Evil. Zemo used an experimental ionic ray to give Williams powers, but the effects would end him if he didn't receive a weekly antidote.
To get the antidote, Wonder Man had to infiltrate the Avengers ranks and deliver them to the Masters of Evil. Wonder Man led his new team into an ambush but changed his mind when the fighting started. He helped the Avengers defeat the Masters of Evil, even though it meant giving up the antidote. Without Zemo's antidote, Wonder Man seemingly perished, but would eventually return and rejoin the Avengers.
When Moondragon came across a planet consumed with war, she decided she would save it and by save it, she meant brainwash everyone on the entire planet to make them stop fighting and then set herself up as a goddess. When the Avengers checked in on her in Avengers #219, she did everything she could to hide how extensively she had used her powers and even forced an entire group of citizens to stage a rebellion.
She tried to convince Thor to help her spread her "peace" throughout the universe, and when he didn't agree with her, she brainwashed him to the point where he fought against the Avengers. When they finally bested her, the Avengers took her to Odin, who put a dampener on her powers.
Despite being one of the founding Avengers, the Hulk didn't stay with Earth's Mightiest Heroes long. After a battle with the Space Phantom, the Hulk believed his new teammates hated him. He quit the team at the end of Avengers #2, and he was already plotting his revenge with the Sub-Marnier in the next issue (they both planned to betray each other as well, but never had the chance).
Namor and the Hulk gave the Avengers a run for their money, but when the battle reached its critical moment, Hulk turned back into Banner -- seemingly from the stress of the fight. Banner ran off and Namor had no choice but to retreat.
7 AVENGER X
When the Avengers found Cressida on a small island, she looked like the perfect secret weapon. Her powers augmented the strength and abilities of her teammates, allowing them to take on groups of supervillains with ease. She quickly received an invitation to join the Avengers and eventually took the name Avenger X.
Unfortunately for the Avengers, their new teammate could only use her power when she drained the life force of nearby people, and she only joined the Avengers for a chance to end the masses and absorb the Avengers’ powers. While she had always planned on betraying her team, her grand reveal happened in Avengers Vol 7 # 4.1.
For a while, Sandman made a legitimate attempt to reform. He received a full pardon from the authorities and even served as a reserve member of the Avengers for a time. During his run as a hero, he also built a rapport with his former enemy Spider-Man. Of course, nothing in comics lasts forever.
Eventually, his old colleague the Wizard used his ID machine to draw out Sandman's old, evil self, and eventually went back to pulling heists and making trouble for the heroes. He even used the rapport he had built with Spider-Man to take the wall-crawler by surprise in a fight.
5 THE PROTECTOR
Noh-Varr the Protector betrayed the Avengers during the "Avengers Vs. X-Men" event, although he didn't side with the X-Men. If the Protector had had his way, he would have helped the Avengers stop the Pheonix Force and continued to serve on their team. As a Kree warrior though, Noh-Varr felt compelled to comply when the Supreme Intelligence ordered him to steal the Pheonix Force sample from the Avengers and deliver it to the Kree Empire.
Noh-Varr obeyed, even though the sample was a critical piece of the Avengers plan to stop the Pheonix Force. When the Protector learned the Kree wouldn't honor their responsibility to protect Earth, he stole the sample back and wanted to rejoin the Avengers. The Avengers, however, wanted nothing to do with him after that.
During a friendly Avengers softball game, both the Avengers and the West Coast Avengers were arrested for treason by Freedom Force, and to make matters worse, the government only went after them because one of their own ratted them out. After a massive search across their ranks, Quicksilver revealed himself as the mastermind in West Coast Avengers Annual #1.
Quicksilver blamed the Avengers for his strained relationships with his sister and his wife, and he gave the government information to get back at them. His plan for revenge also included an LMD version of a villainous group and a giant bomb in the middle of Australia.
3 DR. DRUID
Dr. Druid was still a fairly new addition to the Avengers when he had the sudden impulse to become its leader. He started out by undermining the current leader, Captain Marvel (Monica Rambeau). He quested every move she made and constantly stated that the Avengers needed a stronger leader.
When Captain Marvel had to temporarily step down for medical reasons, Dr. Druid used his mental powers to manipulate the Avengers into electing him as chairman in Avengers #294. As it turned out, Druid himself had been under the influence of Kang's wife Ravonna, who used him to gain control of the rest of the Avengers.
Before he became one of the Dark Avengers, Sentry was one of the New Avengers Captain America recruited. He had unfathomable power, but some serious psychological problems, including an evil persona, the Void. When Norman Osborn offered to help Sentry with his condition, Sentry joined the Dark Avengers.
He took part in the Siege of Asgard and ended up binging the city down in ruins, and when Loki sided with the Avengers to stop Sentry, he took him out. Thor didn't take kindly to either offense, and before he ended Sentry and threw him into the sun, Thor told him that he had betrayed everything that the Avengers stood for.
1 CAPTAIN AMERICA
Possibly the most vicious betrayal in all of Marvel history was when Steve Rodgers turned his back on his team, his country, and everything he ever stood for. During the events that led up to "Secret Empire," Captain America revealed he was a Hydra sleeper agent and had been one since the beginning.
The truth was that a sentient Cosmic Cube rewrote his history so that he was loyal to Hydra, but before that was set to right, Cap killed several of his friends (including his best friend), became BFFs with Zemo, and took over America in the name of Hydra.