The best Marvel villains often define the Earth's Mightiest Heroes. For as enjoyable as the best Spider-Man stories and best X-Men characters have been over the years, they wouldn't be anything without a great Marvel supervillain to help ramp up the drama and centre the action.
Here we have ranked the 10 best Marvel villains from over 60 years of comic book history. Pairing the list down to such a small number isn't easy, but we could honestly be here all day talking about our favorites – we had a similar problem when we put together our best Marvel heroes list too.
10. Dark Phoenix
Despite appearing in earnest in only one major story arc (her namesake Dark Phoenix Saga), the Dark Phoenix/Jean Grey was the central villain in what is, arguably, the most iconic X-Men story ever produced. Partially owing to Jean Grey's prior status as a heroine, and to her destruction of an entire galaxy, the Dark Phoenix remains one of the most shocking and effective villains of Marveldom.
More recently, the Phoenix Force attempted to reunite with the younger, time-tossed Jean Grey - a story which resulted in the return of the older Jean, who banished the Phoenix from her life forever, with the younger Jean eventually returning to her original timeline.
In the aftermath, the Pheonix has since returned to earth and claimed the Avenger Echo as its new host.
9. Doctor Octopus
Until fairly recently, the long-running but sometimes silly Dr. Octopus might have been considered a B-List villain at best, despite often functioning as Spider-Man's arch-enemy. Doc Ock proved his place as one of Spidey's top foes a few years ago by doing what almost no other villains in Marvel Comics have accomplished - he actually finished off his nemesis.
Doc Ock's final scheme was to transfer his consciousness into Peter Parker's body, trapping Peter's mind in Ock's own dying form. In this feat, he actually succeeded, going on to take over Peter's life, and his role as Spider-Man - the Superior Spider-Man, to be precise.
Though Peter eventually defeated Dr. Octopus once and for all, and returned to his role as Spider-Man, many of the things Doc Ock did while under the mask are still affecting his life.
In the years since, Otto Octavius has gone back and forth between his Doctor Octopus and Superior Spider-Man identities, waffling as well on whether he's got a heart of gold or a sadistic streak that still won't quit.
Ultron may be on the back burner in current Marvel Comics, but for decades he has been one of the most violent, vicious foes of the Avengers and the Marvel Universe at large.
A killer AI designed by Avenger Hank Pym before rebelling against his creator and mankind overall, Ultron is obsessed with ending organic life on Earth and destroying humanity in particular.
Unkillable, indestructible, and always scheming somewhere in the background, it's only a matter of time before Ultron resurfaces again, more deadly and dangerous than before.
7. Green Goblin
Norman Osborn has been a villain under many names - as the Green Goblin, the Iron Patriot, and of course under his real identity as the leader of the villainous organization HAMMER (a one-time replacement for SHIELD following the Secret Invasion story). But it's as the Green Goblin, one of the greatest foes of Spider-Man, that Norman built his greatest villainous reputation.
Like many of Spidey's enemies, Osborn is obsessed with menacing the Wall-Crawler, even killing his girlfriend in the story 'The Death of Gwen Stacy,' an event that led to Osborn's own apparent death.
But like the best bad guys, you can't keep ol' Normie down - he eventually resurfaced numerous times, with one of his latest schemes binding him with the Carnage symbiote to become the Red Goblin.
And even after his defeat as Red Goblin, Norman returned as the Green Goblin, pushing Spider-Man so far he actually pushed Norman in turn - right out of an airplane.
Supposedly created when Jack Kirby and Stan Lee pondered what would happen if the Fantastic Four encountered God, the world-eating Galactus quickly became one of the greatest threats ever encountered in the Marvel Universe, often uniting various heroes and even villains when his boundless hunger draws him to the lifeforce rich Earth.
More of a force of nature than a villain in the scheming and plotting sense, Galactus nevertheless constitutes one of the weirdest and most dire threats throughout the Marvel Universe, striking terror into every world on which he casts his shadow.
Still, even Reed Richards of the Fantastic Four, who has faced down Galactus more than anyone, recognizes that Galactus's world-destroying nature is part of the order of the universe, choosing to help guide his terrible hunger rather than try to destroy him.
One of Marvel's most compelling characters almost since his debut in 1963's Uncanny X-Men #1, Magneto has often straddled the line between hero and villain, operating on a morality wholly separate from the usual supervillain dynamic.
And in recent years, Magneto has firmly planted himself alongside the X-Men and the rest of mutantkind on the sovereign mutant nation of Krakoa, solidifying his transition away from being a full-on 'bad guy.'
But Magneto's Marvel Universe legacy in comic books and other media like movies (where Magneto was a main character in most of the now-defunct Fox X-Men franchise), is as a villain - and not just a villain, but one of the premiere menaces of Marveldom, even when his motivations, like preserving mutantkind from extinction, are sympathetic.
For many years, Loki was almost the primary villain of the Marvel universe, menacing not just his brother the mighty Thor, but many of Marvel's other big names, even leading to the formation of the Avengers.
It is, therefore, appropriate that he also took that role in the Marvel cinematic universe, a turn that made Tom Hiddleston a star and made Loki almost more popular among some fans than the heroes he opposes.
These days, in comic books, Loki is one of many popular villains who has moved into being more of an antihero, or even out-and-out superhero, repositioning himself not as the god of lies, but as the god of stories.
In the MCU, Hiddleston's Loki has become a true leading man with his own popular Disney Plus streaming series which will get a second season in 2023.
3. Red Skull
By far the oldest villain on this list, the Red Skull is emblematic of far too many aspects of villainy to list. Never wavering from the Nazi ideals he has espoused since World War II was still being waged, the Red Skull is the absolute counterpoint to Captain America, Marvel's moral center, and provides just about everybody someone to hate.
Red Skull's biggest moment in recent memory came when he instigated Captain America's turn to Hydra (thanks to a Cosmic Cube and some time travel), which culminated in the Secret Empire event in which Steve, as a Hydra dictator, conquered the United States before the 'real' Steve reappeared and saved the day.
Red Skull perished as a result of his own manipulation in Secret Empire, but he recently returned in the finale of writer Ta-Nehisi Coates' Captain America run.
An MCU return for the Red Skull might also be in the cards given the recent official announcement of the fourth Captain America film, New World Order.
2. Doctor Doom
Though his profile has waned somewhat in recent years thanks to a turn as a reluctant hero, the fan-favorite Dr. Doom has returned to villainy in the recent Fantastic Four relaunch, resuming his rightful place in the hierarchy of Marvel's villainous pyramid.
Doom is the smartest man in the Marvel Universe - yes, even smarter than his hated enemy Reed Richards - but like all great villains, his hubris blinds him to his own potential. Not content with mastering only science, Doom is also one of the most powerful magic users in the Marvel Universe and was once considered a rival to Dr. Strange for the title of Sorcerer Supreme.
Despite never having received a proper film adaptation in three movie appearances and two separate franchises, Dr. Doom remains a presence in the cultural zeitgeist, his very name synonymous with villainy even to those who don't read comic books.
Before catching the briefest glimpse of Thanos in the end credits of the Avengers film, most mainstream audiences probably hadn't even heard of the mad titan. But longtime Marvel readers know him as the cosmic bad-ass who possessed the reality-altering Infinity Gauntlet, and who slew half the universe, including many Marvel heroes before his misdeeds were undone.
Now, thanks to his starring role in Avengers: Infinity War and Endgame, Thanos is not just seen as Marvel's biggest villain but he's a household name in his own right - even recreating his cosmically catastrophic Infinity Gauntlet 'snap' to murder half the Marvel Cinematic Universe, just as he did in Marvel Comics.