Scarlet Witch has illustrated that the heroes of the Marvel Cinematic Universe may not always stay on the side of good in Dr. Strange in the Multiverse of Madness. Everybody has a dark side and heroes are no exception as some have a higher potential of becoming evil than others.
Heroes that have become villains in the comics or have shown (or could show) a bit of an evil side to them in the movies are the ones with the potential to be future antagonists. It would be equally entertaining if not more entertaining to see these characters switch their roles and abandon their beliefs.
10 Deadpool
Even in his own movies, it is difficult to call Deadpool a hero as he sees no problem in gruesomely killing his enemies. Deadpool 3 has already been announced as a lineup for future MCU movies with this being the first Fox-connected movie and the first rated R movie for Marvel.
Deadpool Kills the Marvel Universe is a popular comic that could be adapted to introduce Deadpool into the MCU. Not much explaining is needed to make Deadpool a villain as he would try to kill heroes out of boredom.
9 Druig
The member of the Eternals that his own family dislikes uses his power of mind control to control a small civilization to escape War. Druig acts like a rude punk at times but does display that he cares about human life.
The power of mind control is always best used when paired with villains as whoever it is used on loses all control. If Druig can put his needs over humanity, then he could be an Avengers-level threat.
8 Namor
Namor the Sub-Mariner shares similarities to DC’s Aquaman such as the need for his kingdom before his earth. With wings on his feet, Namor has the power to both fly in the air and live in the sea, along with surviving on land with super strength.
Namor is one of many characters that started as a Fantastic For villain before becoming a hero himself. He has been a hero for a while by joining teams such as the X-men in 2011 and the Illuminati. He is rumored to show how powerful of a leader he can be in the upcoming Black Panther: Wakanda Forever film as a possible antagonist.
7 Starfox
Starfox is a member of the Eternals, brother of Thanos, and a member of the Avengers. In the comics, Starfox proved himself a hero by helping the Avengers stop Thanos from gathering the infinity gauntlet.
He has cosmic power along with flight, super strength, and telekinesis, but it is the risky power of stimulating the pleasure senses of the brain that make him a candidate for being a villain. He has misused his power by using it on She-Hulk and with She-Hulk: Attorney at Law introducing the powerhouse heroin, the only thing known about MCU’s Starfox is that Harry Styles will play the character making it possible for these two to go at it on the big screen.
6 Inhumans
With Black Bolt’s surprise return in Dr. Strange in the Multiverse of Madness, it demonstrated that the Inhumans can show up in the MCU. Inhumans are a group of superpower individuals who have gained their power from terrigen mist.
The Inhumans have already appeared in a television series that did not fare well with the audience. Becoming villains can serve as a soft reboot for them. Adapting the X-Men Vs Inhumans comic series would reintroduce the group of superpowered characters while also giving them a bigger spotlight.
5 Mr. Fantastic
Earth-838 had Mr. Fantastic in the role of a hero as he faced the former hero in Scarlet Witch. Something that can separate Reed Richards from the other world from the main continuity is by giving Earth-616 Reed Richards a villainous side.
Much like Tony Stark and Dr. Strange, Reed Richards often lets his own ego get in his way and allows him to put his family and the world at risk. As the Maker, he can continue the MCU legacy of heroes who create their own villains.
4 Hulk
The giant, angry rage monster is feared by all due to his limitless strength. Hulk can be a mastermind villain using other personas such as World Breaker Hulk, Joe Fixit, or Maestro Hulk.
Hulk is a disappointing character in the MCU to many as the anger and fear he brings aren’t shown as much as Bruce’s intellect. Splitting the Hulk from Bruce Banner would give She-Hulk and every other hero in the MCU a new world-threatening threat.
3 Daredevil
Hell’s Kitchen’s vigilante struggles in a moral battle as his fight for justice seems hopeless at times. His morals are thrown out the window when he is possessed by the demon worshiped by the Hand known as the Beast in the Shadowland series.
The Hand has already been established and has been shown to be able to turn heroes into villains using Electra. If he is still believed to be on Captain America’s side, then he is an enemy of the state due to the Sokovia Accords. Align Matt Murdock with the Hand and give up the need to do the right thing and the Avengers can have a new villain to overcome.
2 Moon Knight
The top-ranked rewatchable Disney+ series Moon Knight introduced the world to the mind of Steven Grant and Marc Spector. Although Steven is the passive one, Marc brings violence with him with little hesitation. Add Khonshu to the mix and who is in control attributes to Moon Knight’s attitude.
Moon Knight was viewed as an enemy with his devil-may-care attitude in Avengers vol.8 #33-38 where it went against the heroes to help Khonshu prepare to fight Mephisto. The God of vengeance and the moon is in control and Moon Knight’s fate in the MCU is uncertain, it can lead to him having an intense stare-down with Punisher and taking Thor’s hammer as seen in the comics.
1 Franklin Richards
Franklin Richards is the son of Mr. Fantastic and the Invisible Woman and one of the most powerful omega-level mutants to exist. Franklin can appear in astral form, perceive future events, and reshape reality. Franklin Richards is confirmed to be in a world with mutants in Earth-838 in Dr. Strange in the Multiverse of Madness.
His powers aren’t too dissimilar from the person who took his father away in the MCU, the Scarlet Witch. With scientist parents and the ability to warp reality, Franklin can do like Wanda and travel the universe in search to avenge the person who killed his father. His comic connection to WandaVision villain Agatha Harkness can lead to Franklin Richards traveling to Earth-616 and taking his anger and grief out on the heroes who belong on the home planet of Scarlet Witch.