Marvel’s Phase 6 build-up leaned heavily into scale and spectacle, but 2025 quietly doubled down on menace. Between tentpole releases and Disney+ shows, the studio introduced a diverse roster of antagonists: cosmic terrors, supernatural deal-makers, ruined geniuses, and street-level psychopaths. Together they change the MCU’s risk profile: the threats aren’t only bigger, they’re stranger, darker, and, in many cases, psychologically complicated.
The careful curation of this new villainous roster demonstrates Marvel's commitment to ushering in a darker, more complex era for its shared universe. These introductions are deeply rooted comic book characters poised to become foundational cornerstones for future phases, mirroring the early establishment of figures like Loki and Thanos.
Villains Introduced in the MCU in 2025
Red Hulk (President Ross)
Appeared In: Captain America: Brave New World (Film)
The long-teased gamma-powered transformation of General Thaddeus ‘Thunderbolt’ Ross, now the President of the United States, finally came to fruition in Sam Wilson’s first solo film, Captain America: Brave New World. Portrayed by the legendary Harrison Ford, Red Hulk retains Ross’s strategic military mind and political authority, even shooting a gun in a scene that got cut out. He is now coupled with the immense, nearly invulnerable brute strength of a Hulk, colored red due to a variation of gamma exposure.
The Red Hulk’s introduction is critical because it repositions a classic adversary from a relentless military man to a terrifying, government-sanctioned weapon. While not the main manipulator of the film, his transformation serves as a monumental physical threat to Sam Wilson’s Captain America, showcasing the sheer power required to stop him, notably by being able to shrug off a volley of bullets but vulnerable to weapons made of Vibranium, like Cap’s new blades.
The character’s establishment as the new Hulk-level threat sets the stage for future confrontations, potentially fulfilling the fan-favorite comic prophecy of a monumental Hulk-versus-Hulk showdown.
The Leader (Samuel Sterns)
Appeared In: Captain America: Brave New World (Film)
Samuel Sterns, who was last seen in The Incredible Hulk absorbing gamma-irradiated blood that began to swell his skull, returned after nearly two decades as the hyper-intelligent villain known as The Leader. Reprised by Tim Blake Nelson, Sterns is the primary antagonist and mastermind behind the tumultuous events of Captain America: Brave New World.
The MCU’s Leader is a major force of organized chaos. While retaining his superhuman intelligence, which allows him to predict the outcome of almost any action, the MCU version grounds some of his comic book abilities. For example, he can use technology that affects mind control via light and sound rather than relying solely on telepathic powers.
With an enlarged, craggy skull-brain (achieved through practical prosthetics and subtle CGI), the Leader's visual appearance was initially made more monstrous than the version portrayed in Brave New World.
Sidewinder (Seth Voelker)
Appeared In: Captain America: Brave New World (Film)
Giancarlo Esposito made his highly anticipated MCU debut as Seth Voelker, the villainous Sidewinder, in Captain America: Brave New World. In the film, Sidewinder appears as the highly intelligent, methodical leader of a powerful mercenary organization hired by The Leader to carry out their deadly schemes.
This depiction marks a significant departure from the comic book version of Sidewinder, who traditionally possesses a specialized cloak allowing him to teleport and is the founder of the snake-themed Serpent Society.
The MCU’s decision to strip the character of his superpowers and instead portray him as a cold, calculating, and strategic mercenary leader, a type Esposito has mastered in his career, made Sidewinder a more grounded character.
The Hood (Parker Robbins)
Appeared In: Ironheart (Disney+ series)
Parker Robbins, known as The Hood, is the magical villain and main antagonist of the Ironheart series. Portrayed by Anthony Ramos, Robbins was established as a rising criminal figure whose powers stem from a red hooded cloak and boots stolen from a demonic source. This mystical attire grants him abilities such as limited teleportation, levitation, and temporary invisibility.
The Hood’s introduction is a pivotal moment as he serves as the perfect foil to Riri Williams’ technological genius, creating a dynamic conflict between science and magic. Crucially, his origin ties directly into the MCU’s growing supernatural landscape, establishing a clear link to demonic forces.
His descent into dark magic (which manifests physically with dark, red veins under his skin) and the more he uses the cursed objects sets him on a path to becoming a major player in the magical underworld.
Mephisto
Appeared In: Ironheart (Disney+ series)
After years of rampant fan speculation and countless teases, the demonic powerhouse Mephisto officially entered the MCU in the finale of Ironheart, portrayed by Sacha Baron Cohen. A character often equated with the Devil in the Marvel universe, Mephisto is an immensely powerful entity whose primary goal is the collection and manipulation of mortal souls.
The critical nature of Mephisto’s debut is his immediate tie to a new hero’s origin. He is revealed to be the true source of the power and corruption behind The Hood’s magical artifacts, making him the ultimate puppet master of the Ironheart series. Mephisto’s most sinister move is offering Riri Williams a deal to resurrect her dead friend, Natalie, which Riri ultimately accepts, with the ominous consequence of a red vein appearing under Natalie’s skin.
This direct deal with a major hero and the theme of soul-bargaining firmly establish Mephisto as a high-stakes, overarching supernatural antagonist for the Multiverse Saga, potentially gathering the spiritual forces necessary to confront the heroes in a future Midnight Sons film.
Muse (Bastian Cooper)
Appeared In: Daredevil: Born Again (Disney+ series)
Muse, whose civilian identity is revealed as Bastian Cooper, was introduced as a central antagonist to Matt Murdock in the Daredevil: Born Again series. Portrayed by Hunter Doohan, this version of Muse is a human serial killer and former Taekwondo student who is driven to create horrific, shock-value street art. His victims are often immortalized in murals across the city.
The character’s development is crucial to the series’ tone, adding a layer of sophisticated, psychological horror that pushes the boundaries of the MCU’s street-level narrative. A major change from the comics is the revelation of his identity through a chilling therapy session with Heather Glenn, who inadvertently helps him unlock his true, murderous nature.
Muse’s chaotic actions are quickly exploited by Wilson Fisk, who uses the fear generated by the villain’s murders to justify the creation of his new Anti-Vigilante Task Force (AVTF). This turns the public narrative against Daredevil and other masked heroes.
The Mole Man (Harvey Elder)
Appeared In: The Fantastic Four: First Steps (Film)
Dr. Harvey Elder, the Mole Man, made his MCU debut in The Fantastic Four: First Steps, portrayed by Paul Walter Hauser. In the film, he is established as a former enemy of the Fantastic Four and the current, unifying leader of the subterranean Moloids.
The MCU significantly alters the Mole Man’s comic origin, where he was a scorned scientist seeking to punish the surface world, by making him an organized leader and ambassador for the underground civilization of Subterranea. His conflict with the Fantastic Four is driven by a desire for revenge against the surface world, whose rampant construction caused numerous tunnel collapses and threatened his Moloid society.
By commanding the colossal monster Giganto to attack New York, he forces the newly formed Fantastic Four into their first major public battle. His complex motivations and the fact that Sue Storm later negotiates with him to use Subterranea as an evacuation point against Galactus suggest a possible future as a powerful anti-hero or reluctant ally, rather than a one-dimensional villain.
Sentry/The Void (Robert Reynolds)
Appeared In: Thunderbolts (Film)
Robert "Bob" Reynolds, a man gifted with the power of the Sentry, was introduced in Thunderbolts, portrayed by Lewis Pullman, but is inherently linked to his dark, destructive alter-ego, The Void. The Sentry’s power comes from a variant of the Super-Soldier Serum, which is stated in the comics to be 100,000 times more potent than Captain America’s, granting him abilities like immense strength, invulnerability, energy manipulation, and potentially reality manipulation.
The central conflict of this character is the internal battle between the benevolent Sentry and the nihilistic Void, which is a literal manifestation of Reynolds’ subconscious darkness. The Void is revealed as the core threat the newly formed Thunderbolts team is tasked with containing or eliminating.
His power level is astronomically high, and he is said to possess the power of one million exploding suns; he immediately fills the power vacuum that Thanos and other phase villains left. Sentry’s confirmed return in Avengers: Doomsday confirms his role as a pivotal, unpredictable force who may swing between hero and catastrophic villain in the escalating Multiverse Saga.
Galactus
Appeared In: The Fantastic Four: First Steps (Film)
Galactus, the Devourer of Worlds, made his highly anticipated, corporeal debut in the MCU’s The Fantastic Four: First Steps, portrayed by Ralph Ineson. This is a critical development, as the MCU avoids the much-maligned space cloud version of the 2007 film by presenting the character in his full, towering, purple-and-blue armored form.
Galactus is a cosmic entity whose existence is sustained only by draining the life energy from planets. In this film, his arrival is foreshadowed by his herald, the Silver Surfer (Shalla-Bal). Galactus’s ultimate threat against Earth is a calculated transaction: he senses the immense cosmic power of Reed and Sue Richards’ unborn child, Franklin, and attempts to claim the child’s energy to sate his hunger.
This twist immediately elevates the Fantastic Four’s importance to a cosmic level. It sets up Galactus as an existential threat to Earth and the entire universe, making him one of the most significant and highest-stakes villains ever introduced into the MCU.
Geraldo Amartey is a writer at The Direct. He joined the team in 2025, bringing with him four years of experience covering entertainment news, pop culture, and fan-favorite franchises for sites like YEN, Briefly and Tuko.
