Although the MCU movies are mainly known for their epic battle sequences and hilarious quotes, one thing that has begun to become a popular staple in the franchise is the rise of complex villains. Just recently, Thor: Love & Thunder and She-Hulk used this effectively as they managed to capture Gorr the Butcher's tragic backstory and Emil Blonsky's path to redemption.
Although no one is condoning the villains' actions, many MCU fans, particularly on Reddit, have agreed that the complex antagonists are a lot more fascinating to watch since they make for interesting character studies and add a lot more weight to the story.
Wanda Maximoff
Wanda had evolved tremendously throughout the MCU timeline. She started as a villain, became an Avenger, and in Multiverse Of Madness, she returns to her evil ways once again. Her arc in WandaVision, however, allowed viewers to sympathize with her as they finally saw the grief and pain she experienced come out (which was also shown in Multiverse of Madness).
For Reddit user ducduckduc, they said the moment "Wanda realized the [screwed up things] she'd done under corruption and went speechless in front of her kids" was one of the most heartbreaking scenes, especially the way the audience could see her pain in her "facial expressions." While Wanda has certainly got a long way to go before she can gain forgiveness, some fans did feel a bit of sympathy for her since they knew that she was trying to find some happiness. Unfortunately, she took a dark path to try and get it.
Hela
Hela is Odin's first-born and only daughter. She is exiled after she tries overthrowing her father, and upon Odin's death, she returns to wreak havoc on Asgard.
Reddit user grandmofftalkin states they felt sorry for Hela since "she does her father's bidding, he casts her out to some phantom zone because of it" and then discovers "he's erased every trace of her existence" when she returns. Many MCU fans believe that Odin is one of the worst parents in the MCU; Hela grew to be vindictive toward him, and maybe there's a valid reason why. Her actions upon her return are obscene, but it's easy to sympathize with the person she likely was before spreading turmoil and death became her main concern.
Adrian Toomes/Vulture
The Vulture is a Spider-Man villain who uses alien tech to enhance and sell dangerous weapons on the black market.
While Adrian Toomes should not be illegally selling and transporting such goods, the reasoning behind his actions is easy to sympathize with. Cowpool20 says, "You have to feel for Vulture. Dude is just trying to provide for his family and gets [screwed] over by the rich." Although no one is forgetting the dangerous crimes he committed, Toomes did just want to make sure that his family was well-off. Fans saw firsthand how much he loved his daughter more than anything in the world and was very protective of her. His motives might have been right but the execution was all wrong.
Zemo
Zemo is the main villain in Captain America: Civil War. He single-handedly tears the Avengers apart, seeking revenge for his family who died because the Avengers failed to protect them.
Reddit user MissSweetMurderer expresses sorrow for Zemo, saying, "His motivation is so, so real. His pain in [the scene with T’Challa] is heartbreaking. And now he's alive but doesn't even have his wife's voicemail anymore." While there's certainly no one condoning his actions and the crimes he committed against Wakanda, many were able to relate to Zemo in this instance since grief is something that affects everyone. While The Falcon & The Winter Soldier brings him back as a far lighter character, his grief is still present, especially when he gives Turkish delights to some displaced kids (in a great callback to his monologue in Civil War).
Wenwu
Wenwu is the ancient and authentic Mandarin as well as the founder of the Ten Rings. He is also the father of Shang-Chi and a widower (which is greatly explored in Shang-Chi).
Tekki777 says, "He [wasn't a great] person, especially to his kids, but he was legitimately someone stuck in grief, which not only wrecked his relationship with his kids, but it was ultimately what led to his death." Wenwu did terrible things, and there is no excuse for that. He is the head of a terrorist organization that ruthlessly attacks and kills its enemies. However, concerning his family life, especially the death of his wife, it's hard not to feel an ounce of sympathy for the man. As the MCU has shown time and again, grief can cloud someone's judgment and make them do unspeakable things. He just wanted a chance to see his wife again, and unfortunately for him, the Dweller took advantage of his pain.
Erik Killmonger
Killmonger is the son of Prince N'Jobu, who was killed for trying to bring vibranium to less fortunate communities and attempting to murder Zuri for exposing his secrets. Since losing his father, Erik made it his life mission to finish what N'Jobu started. Though he has no powers, he's extremely dangerous.
Like many other MCU villains, Killmonger does the wrong things for the right reasons. Gjp11 explains, "Yes his methods were wrong, yes he was clouded by his generational trauma. But his goal, the liberation of a race that to this day still faces ridiculous oppression wasn't wrong. I feel passion for his cause... and I genuinely felt bad for his death, even if it was necessary." Unlike T'Challa, Erik grew up in a world of discrimination and all he had was his dad. N'jobu was taken from him, and it's not so hard to believe he'd want to seek revenge on those who are to blame.
Ava Starr/Ghost
Ghost is the alter ego of Ava Starr. When she was young, she lost her parents in an accident with quantum energy. This same event gave her the cursed ability to phase in and out of tangibility. SHIELD took advantage of her and used her as a weapon.
When Ava discovers she's dying from a lack of quantum energy, she tries to steal Hank Pym's tech and absorb the quantum realm. Im_Daydrunk shares, "I think she's definitely got one of the most understandable and sympathetic motivations. Pretty much every single person would be doing the same thing in her situation." Her arc in Ant-Man & The Wasp is very sad. Her desperation for the energy is apparent, she just goes about getting it the wrong way.
Nebula
Nebula is an adopted daughter of Thanos and Gamora's sister. In the first Guardians of the Galaxy film, she plays a villain role as she tries to get the orb for her father.
Redditor A_Sarcastic_Whoa reflects on one of Nebula's toughest moments, saying, "She's ripped apart and shoved full of cybernetic parts and spends her entire life trying to please Thanos who will never love her as much as he loves Gamora." Nebula seeks approval from Thanos and becomes angry when she doesn't get it. She then takes it out on Gamora because that's all she knows how to do. Like Hela, this is a woman who is traumatized by her father's apathy. Fortunately, she is able to break ties with Thanos, and she becomes one of the good ones.
Loki
Dubbed the God of Mischief, Loki is a frost giant and the adopted brother of Thor. He also had one of the most interesting character arcs in the Thor movies.
Reddit user sere1 observes the character, saying "The MCU has a long-running habit of making you feel bad for Loki." They have a point. From the reveal about his lineage to his reaction to Frigga's death, he has all the sympathy from viewers. Given that he also lived in Thor's shadow for most of his life and spent most of his time seeking his father's approval, it's also not surprising that few fans are able to understand his complex mind since this issue can be relatable as well.
Gorr
Gorr is the villain of the latest Thor movie. After watching his daughter die and meeting the authentic persona behind the god he's always praised, he's chosen by the necrosword and becomes the god butcher.
Gorr is one of the best villain characters in the entire MCU. LittleYellowFish1 exclaims, "After going through all that loss and suffering and then being mocked by the very god that was meant to save you, most of us would probably pick up that sword too." Gorr is seeking the destruction of all gods, and not a lot of fans can blame him. Almost all the gods that have been introduced in the wider franchise are arrogant and selfish. Even Thor started that way in his first movie. With the mix of grief and a cursed sword's persuasive words in his ear, it's completely understandable why he did what he did.