The upcoming Thunderbolts film in the MCU Phase 5 has the potential to introduce some powerful, if lesser-known, villains to the franchise. The team has had many iterations, led by the likes of Baron Zemo and Norman Osborn in the comics. While the starting roster of the MCU's Thunderbolts team has been revealed, who exactly they'll be up against or who may join their ranks throughout the movie remains a mystery.

Some subterfuge and double-crossing from the MCU's Thunderbolt's director, Valentina, could paint the CIA director as a likely twist villain pulling the strings. But the MCU's Thunderbolts still need some bombastic super-powered criminals to fight, and these lesser-known antagonists from the comics who have yet to have a true MCU debut are great candidates. In addition, with the Thunderbolts being an ever-changing patchwork team of shifting allegiances and villains trying to make the most of their circumstances, there's a strong possibility that some of these names could wind up on the team by the film's end.

10 Headsman

Before becoming Headsman, the aptly named Cleavon Twain was a member of a biker gang out of Louisiana, the Headhunters. Learning to fight in bars and making a name for himself as a criminal, Cleavon was eventually sponsored as a villain by Norman Osborn, granting him the cutting-edge technology that allowed him to fully adopt his Headsman persona. In the comics, he is used as a pawn by Osborn, taking advantage of his brute force bravado and lack of questions to further the Green Goblin's own nefarious ends.

Headsman has access to an arsenal of Oscorp-built experimental technology, including a harness that enhances his strength, a flying disc similar to the Goblin Glider, and his signature adamantium-alloy axe. With these weapons, he was nearly able to put down Spider-Man in the comics. While the events of Spider-Man: Now Way Home did away with Norman Osborn, leaving him cured of the Goblin and back in his home reality, criminals appropriating scavenged technology has historically been a common practice in the MCU.

9 King Cobra

Klaus Voorhees was an ex-convict on the path to redemption, working in medical research with the esteemed Professor Ezekiel Shecktor. In their goal to create a universal antivenom for snake bites, Voorhees' criminal urges got the better of him; consumed with jealousy of Professor Ezekiel's success, he staged a fatal snake bite accident but wound up getting himself bitten in the process. Thanks to a combination of radioactive snake venom and experimental anti-toxin coursing through his veins, Vorhees developed snake-like powers, becoming King Cobra. Later, he was forced to join the Thunderbolts as a result of the Superhuman Registration Act following the Civil War storyline of the comics.

Essentially a serpentine version of Spider-Man, the radioactive snake that bit King Cobra grants him superhuman elasticity, flexibility, and durability. A great contortionist, Voorhees excels at slithering behind enemy lines before unleashing his variety of poisonous venoms and toxins. His snake-like nature extends to his personality as well, being one of the Thunderbolts to help organize a rebellion against the government-funded version of the team's interests. King Cobra would be a fantastic choice to serve as a double-crossing Thunderbolts member to sell the team's instability and air of subterfuge.

8 Nuke

One of the most unstable and dangerous members to ever grace the Thunderbolts' roster, Frank Simpson was a P.O.W. of the Vietnam War. Suffering torture at the hands of Wolverine, Simpson had the American flag tattooed on his face, and his mind shattered. Similar to The Winter Soldier, he was implanted with trigger words that threw him into explosive fits of violence, capable of taking out entire villages single-handedly. From there, he was inducted into the Project Homegrown, a program similar to Weapon X that enhanced his biology, granting him cybernetic enhancements, a second heart, and incredibly durable skin.

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Will Simpson, a version of Nuke, has appeared in Netflix's Jessica Jones series. The Netflix version of Nuke uses experimental pills to increase his combat capabilities, though at the cost of his own sanity. The Nuke of Marvel's comics uses similar pills to control his bouts of rage and effectiveness in battle. While Marvel's Netflix series integration into the MCU may be dubious, Nuke has still yet to make an appearance in the MCU proper. It's possible that Frank Simpson could be introduced as a relative of Will, sharing his unfortunate fate as a killing machine before barreling into the Thunderbolts.

7 Paladin

More of a mercenary than a straight-up villain, Paladin is a skilled fighter and investigator who has had his fair share of brushes with Marvel's heroes. One of Marvel's few masked characters whose name and origin are yet to be revealed, little is known about Paladin's past other than the fact that he was a private investigator. As a member of Norman Osborn's version of the Thunderbolts, Paladin was unique in having something of a moral compass: He had qualms about unnecessary killing, preferring to use his signature stun gun when possible.

In addition to his sense of honor, Paladin is also known as being something of a ladies' man, even briefly dating The Wasp at one point in time. Despite his less-than-villainous traits, Paladin is still an unabashed mercenary, doing jobs for the highest bidder that have brought him up against the likes of Daredevil and The Punisher. Paladin perfectly embodies the shades of gray morality that Thunderbolts team thrives in, and as such a malleable character, he would be easy to slot in the MCU anywhere a highly-trained threat is needed.

6 Mac Gargan's Venom

A career criminal, Mac Gargan is better known as his original alias, Scorpion. However, he also had a tenure as one of Spider-Man's more prominent villains. Approached by the Venom symbiote, Mac Gargan gains notoriety and power beyond anything he experienced as Scorpion. As a member of the Thunderbolts, Gargan is even able to gain some notoriety as a hero among the public. Beset by the same violent urges that other users of the Venom symbiote experience, however, he is limited with implants that shock him should he lose control of the parasite.

Mac Gargan has made a brief appearance in the MCU thanks to Spider-Man: Homecoming, in which he's seen in prison alongside Vulture. In the MCU, Gargan hasn't been seen in full-costume as Scorpion yet, and it's unclear whether he had already had his time as the arachnoid villain before being put behind bars by Spider-Man. But with a leftover piece of Tom Hardy's Venom symbiote clearly being deposited in the MCU as of Spider-Man: No Way Home, Mac Gargan's Venom in the MCU is more possible than ever.

5 Swordsman

The Disney+ Hawkeye series introduced Jack Duquesne, better known in Marvel Comics' Swordsman. Essentially a sword-based version of Hawkeye, Jack Duquense's Swordsman is more of an anti-hero than a villain, but he wasn't the only character in the comics to use the persona. The title of Swordsman was also used by Andreas Von Strucker, child of elite HYDRA agent Baron Strucker. Along with his twin sister, Andrea, Andreas was a super soldier from birth, genetically modified in utero. The program was a success, granting the pair flight and energy-blasting powers they could use so long as they were touching.

Andreas fell in with the Thunderbolts after the death of his sister, taking the alias of Swordsman. Wrapping the hilt of his signature sword with his sister's skin, he was able to maintain his powerful blasts of energy, in addition to his skills with a blade. Swordsman could be an excellent antagonist to rope HYDRA, a prominent villainous force within the MCU, back into the picture, keeping the Thunderbolts on their toes.

4 Radioactive Man

A deranged nuclear physicist from China, Chen Lu experimented on himself with radiation, successfully granting himself powers after slowly building his body's ability to withstand radioactive forces. Transforming himself physically, Radioactive Man's skin glows bright green as he manipulates radiation on the microwave spectrum for a variety of effects, able to emit beams of heat, EMPs, and energy constructs. As Radioactive Man, Lu frequently clashed with the Avengers as he sought to take over the world.

As a villain, Radioactive Man is almost refreshingly simple: a mad scientist bent on world domination fighting with one of the most terrifying forces in nature. Despite this, he is one of the few villains who joins the Thunderbolts willingly in an attempt to atone for his past. During his tenure in the Thunderbolts, he absorbs an incredibly high amount of radiation while on a mission, forcing him to constantly wear a shielding suit or risk irradiating anyone around him. Whether the MCU opts to leave Radioactive Man as an unashamed big bad or a morally conscious anti-hero averse to hurting those around him, he'd be a welcome inclusion.

3 Mr. X

For all the promises of redemption a spot on the Thunderbolts might offer a villain, Mr. X is a truly unredeemable monster who only joins the team out of boredom. Originally a successful business executive, Mr. X is a serial killer whose latent mutant abilities were unlocked thanks to his fascination with death. Using his inherited fortune, Mr. X traveled the world, training under high-ranking martial artists before killing them, scarring his body with a mark for every victim. In addition to being in peak physical prediction, Mr. X's powers allowed him to predict his opponent's every move, making him unbeatable to ordinary humans.

Unsurprisingly, Mr. X's first brush with the Thunderbolts in the comics was as a target, the clandestine group sent to assassinate the prolific serial killer. However, the mission turned out to be one of recruitment, Mr. X joining the team hoping it could lead to a challenge for his abilities. Mr. X would be a true test of the moral ambiguity of the team, the value proposition of his skills versus his appalling criminal acts being allowed to go unpunished being something the current MCU lineup of the Thunderbolts would struggle with.

2 Screaming Mimi

Melissa Gold has a colorful history, becoming a wrestler after running away from home at a young age and adopting the name "Screaming Mimi" alongside her team, the Grapplers. The team later turned to crime after receiving powers courtesy of the Power Broker, a major crime boss who ran the Power Broker Corporation, a criminal organization that sold powers to the highest bidder. This gave Melissa enhanced vocal cords that granted her power of sound, able to scream at incredible volumes and create constructs of pure sound.

Screaming Mimi joins a version of the Thunderbolts run by Baron Zemo under the name Songbird. Though she shares the villainous origins of most of the team's members, she grows to adapt to her role as a hero over time. Songbird even helps the Thunderbolts in turning against Zemo, rescuing the Avengers and thwarting his plans of world domination. The Power Broker's inclusion in the MCU could make for a great jumping-off point for introducing audiences to Melissa Gold in Thunderbolts, be it as Screaming Mimi or as Songbird.

1 Satana

One of the most powerful characters to ever brush with the Thunderbolts, Satana Hellstorm is the half-demon child of Marduk Kurios, a powerful evil entity in Marvel's cosmology. Taken from Earth at a young age and transported to her father's dimension, Satana learned the family business quickly, excelling in black magic, and was given a magical familiar named Exiter. She was then sent back to Earth as a Succubus, causing chaos and claiming victims across the U.S., turning the souls of men she seduced into butterflies and eating them for sustenance.

Satana is one of the most powerful, yet also self-centered, members of the Thunderbolts to date. Coerced into joining the team, Satana was quick to stage an escape with her fellow members. In a magic mishap, her escape attempt leaves her and the other members stranded in the past, where they meet the original Baron Zemo's first version of the team in World War 2. This could be a great opportunity for Thunderbolts to explore the team's full lineage, and with the MCU steadily introducing more of the supernatural into the fold, Satana could be an excellent choice for a chaotic assignment for the Thunderbolts to grapple with.