Warning: This list includes spoilers for Doctor Strange in the Multiverse of Madness.
The Marvel Cinematic Universe is home to great vigilantes, but some of these truly daring individuals are not as heroic as they appear. While the Avengers team may possess noble intentions, a few of their actions appear somewhat questionable, with their violent approach to battling evil placing the lives of innocent civilians at risk.
These members of Marvel Studios' crime-fighting team have engaged in some particularly horrendous deeds, which would impress many of their greatest villains. These characters' murky behavior place significant doubt over their place within the Avengers roster, as their controversial exploits, blur the lines between "good" and "evil."
Scarlet Witch
Wanda Maximoff has lived a deeply troubled life throughout the shared cinematic universe, as she loses her loved ones to a few of the Avengers' biggest foes. These hugely traumatic experiences lead to the Scarlet Witch making several morally dubious decisions, as she struggles to cope with the loss of her parents, Vision, and her brother Pietro.
Wanda's most despicable crusade involves her enslavement of Westview in WandaVision, which sees the deeply troubled witch entrap the town's residents within a fabricated sitcom reality against their will. Westview's inhabitants are denied the chance to visit their families and are instead subjected to experiencing Wanda's deep trauma, making this a deeply immoral move from the Scarlet Witch. She took it a step further in Doctor Strange in the Multiverse of Madness, going full-on villain and murdering hundreds in her quest to find her kids in an alternate universe.
Rocket Raccoon
Primarily a member of the Guardians of the Galaxy, Rocket Raccoon joins the Avengers in Avengers: Infinity War, providing valuable assistance for the team across the thrilling motion picture, and its sequel Avengers Endgame. The snarky raccoon has provided some of the MCU's greatest quotes, however despite his more recent heroic feats, the Guadians' mechanic possesses a much more nefarious past.
Rocket's many crimes include multiple arson attempts, and several counts of theft, while the genetically modified creature has also acted as a mercenary for hire on behalf of various intergalactic criminals. His later adventures with the Guardians Of The Galaxy see this devious being attempt to steal Anulax batteries from the Sovereign, placing his teammates in serious jeopardy as Ayesha declares war on the Guardians team.
The Winter Soldier
Real name Bucky Barnes, the Winter Soldier is one of the MCU's most tragic figures, with Steve's best buddy having been unwillingly forced to commit numerous terrible deeds. The World War II soldier finds himself brainwashed by Hydra following his fall from the roof of the Schnellzug EB912 train, and his work for the supervillain organization sees him undertake various villainous endeavors.
As Hydra's ruthless soldier, Bucky exacts several successful assassinations of the Nazi group's greatest enemies. Furthermore, the Winter Soldier is later revealed as the man responsible for the deaths of Tony Stark's parents Howard and Maria, coldly dispatching of the tech genius's beloved parental figures, in one of the MCU's most callous events.
The Incredible Hulk
Considered by many to be the strongest Avenger, The Incredible Hulk is one of the team's most notorious members, with the angry green giant having played a key role in many of their greatest battles. Bruce Banner's monstrous alter-ego also proves to be something of a liability, however, as his considerable strength and uncontrollable rage cause an immense amount of destruction.
Featured among the Hulk's most questionable actions are his violent rampage at the Kirby bar and his vicious attack on the city of Johannesburg and its citizens under Wanda's influence. Additionally, Bruce's alter-ego erupts into a vicious rage at the Culver University's laboratory, and his malevolent behavior leaves Betty Ross alongside many of the university's graduate students seriously injured.
Nebula
As an adopted daughter to Thanos, Nebula has lived a shady past, with the ruthless assassin having caused the deaths of many intergalactic individuals. The cold and emotionless space pirate enlists with the Avengers during the events of Avengers: Infinity War and Avengers: Endgame after losing her sister Gamora, however, her dark history reveals this character to be one of the superhero ensemble's most diabolical teammates.
Nebula's early history working on behalf of Thanos leads to her heartless slaughter of half of the Korbinite race, as her Dad seeks to claim the immensely powerful Infinity Stones. Later, Nebula engages in the savage massacre of the Klyn prison, as she grimly eliminates the facility's guards and prisoners, proving herself to be a particularly devilish individual.
Doctor Strange
Doctor Strange's MCU appearances have seen him deliver some of the universe's most memorable quotes, with many fans believing the Multiverse Of Madness trailer to contain some of the franchise's best lines. While the indomitable sorcerer has helped to save the universe on numerous occasions, his arrogance has previously led to the former surgeon making some morally deplorable decisions.
His treatment of Peter Parker, in particular, leaves little to be desired, with Stephen Strange taking a decidedly aggressive stance against the young vigilante's belief that the multiversal villains can be rehabilitated, preferring to cruelly send these new arrivals back to their deadly fates rather than trust in his web-slinging friend. Strange sends Spider-Man to the mirror dimension and maliciously attacks the well-meaning teen with his spellcasting abilities, showing little concern for the welfare of either Peter or the multiversal beings Peter believes can be changed.
Black Widow
Acting as a top-secret operative for SHIELD, Black Widow is a truly courageous individual, as she helps her Avengers teammates battle some of the universe's most fearsome foes. Although her later years see her embrace a more heroic lifestyle, Natasha Romanoff's backstory showcases a more dishonorable side to the dark vigilante, with the strong fighter having previously worked as an assassin.
After years of training through the Red Room, Natasha graduates from the "Black Widow" program and goes on to assassinate a huge number of potential threats to the Soviet Union. Meanwhile, her defection to SHIELD sees her blow up Dreykov's Budapest office, despite possessing the knowledge that his young child Antonia was inside, presenting a sadistic and disdainful aspect of Black Widow's personality.
Iron Man
Often regarded by fans as the best Avenger, Iron Man has been present since the MCU's early beginnings. However, while Tony Stark has proven himself to be one of the Earth's mightiest heroes on many occasions, he has also demonstrated some truly evil traits, with his contentious actions having caused several of the universe's biggest threats to emerge.
Tony's callous disregard for people results in the creation of two of Spider-Man's greatest villains, as Adrian Toomes and Quentin Beck assume the mantles of the Vulture and Mysterio respectively, to act on their grudges against their former boss. His most morally dubious act, however, is his decision to enlist Peter Parker in the airport fight against Captain America and his loyal friends, even though Peter is only a teen, showing a shocking lack of care and responsibility from the playboy billionaire.
Ant-Man
Real name Scott Lang, Ant-Man is one of the superhero universe's most notorious crooks. His dishonest behavior sparks the interest of the original Ant-Man Hank Pym, who views Scott as the perfect man to take on the famous vigilante moniker. Cassie's layabout Dad has built up quite the criminal record, making him an especially dodgy member of the Avengers roster.
One of his most infamous heists sees Scott break into the Vistacorp headquarters, where he hacks into the company's systems and steals thousands of dollars from their accounts. The future Ant-Man's diabolical conduct continues with his theft of Geoff Zorick's car, which he proceeds to drive into the millionaire's pool. Scott's disgraceful attitude lands him with a three-year prison sentence, leaving his young daughter Cassie without her father, marking this as one of the Avengers' most appalling exploits.
Hawkeye/Ronin
Working as an agent for SHIELD, Clint Barton has committed some noble feats. His remarkable skillset in light of possessing no superpowers is especially impressive, as he joins the Avengers as Hawkeye in protecting the universe from various dangerous beings, however, Clint's abilities have also been used for some of the franchise's most shocking events.
Upon losing his family to Thanos's snap, Clint undertakes the superhero mantle of "Ronin," acting as a merciless executioner for the world's most fearsome criminals. Among the grief-stricken hero's most heinous deeds during this time include his slaughter of several Tracksuit Mafia members, and also his brutal massacre of the Yakuza organization in Tokyo, solidifying Clint as one of the MCU's most malevolent Avengers.