Over the course of their sixty years in comics, the Fantastic Four have faced the greatest villains in the Marvel Universe. What's worse is that many of their greatest foes not only come back again and again but routinely power-up, making each encounter even more challenging than the last.

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From Doctor Doom to Kang The Conqueror, the Fantastic Four face threats from across time and space. Their mos powerful villains utilize magic, time travel, and the Power Cosmic, making the success of the Fantastic Four unlikely in most instances. With every new adventure, the challenge becomes harder and harder.

Namor

Namor uses the Phoenix Force to unleash a tidal wave against Wakanda in Marvel Comics.

Namor the Sub-Mariner possesses superhuman strength and stamina, making him one of the strongest enemies of the Fantastic Four. He can also fly and swim at tremendous speed and impressive depths.

Though he pales in comparison to some cosmic threats, he did briefly serve as host to the Phoenix Force during the Avengers Vs. X-Men crossover event. With the god-like power of the Phoenix at his disposal, he leads a devastating attack against Wakanda, making him a truly powerful villain.

The Impossible Man

The Fantastic Four confront the Impossible Man in Marvel comics.

The Impossible Man is an alien shapeshifter from the planet Poppup who can take the form of any being or object. He can also mimic the powers and abilities of other beings, making him extremely powerful. The Impossible Man is able to teleport across dimensions, able to jump back and forth between Earth and the Negative Zone or his own native planet.

He isn't as menacing a threat as others, and primarily is a source of mischief and havoc who is always looking for attention.

Mephisto

Mephisto sits on his throne in Marvel Comics.

Mephisto is a demonic entity with extraordinary power, particularly in his own dimension. Mephisto's powers in the comics include broad ability over magic and sorcery, shapeshifting, and immortality. He can also acquire souls, making him especially dangerous.

Mephisto has been a thorn in the side of many Marvel characters, but the Fantastic Four especially. In the limited series Mephisto Vs. Fantastic Four, he goes after Franklin Richards, the son of Reed and Sue, whose reality-warping powers threaten Mephisto's own.

Annihilus

Annihilus opens his mouth as fire rages behind him in Marvel Comics.

Annihilus hails from the Negative Zone and is among the strongest and most durable Fantastic Four foes thanks to his insectoid-like armor. He is also able to fly and operate in space, allowing him to move freely back and forth between dimensions in major events like Annihilation.

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By far his most powerful asset is the Cosmic Control Rod, a weapon that can manipulate matter and energy. The rod also has the added benefit of supplementing his own living energy, making him virtually immortal.

Thanos

In three panels, Thanos snaps his fingers in the Marvel comic series Infinity Gauntlet.

Thanos became a major problem for the Fantastic Four right when he did for everyone else in the Marvel Universe. Using the Infinity Gauntlet, Thanos snapped half of all life from existence, including the entire Fantastic Four team.

With the enormous cosmic power afforded to him by the gauntlet, Thanos is one of the most powerful villains they have ever faced - though they didn't have the chance to initially. And comic book fans know the Silver Surfer played a key role in defeating Thanos and undoing The Snap in the comics.

Kang The Conqueror

Kang The Conqueror dons helmet of his suit of armor in Marvel Comics.

Kang The Conqueror has command of very advanced technology from the 30th century, including a suit of battle armor that gives him superhuman strength and stamina. Beyond that, and his incredible intellect, Kang is incredibly powerful in his infinite supply of Kang variants.

Kang's actions in the multiverse have created an endless army of variants for the Fantastic Four, Avengers, and others to confront. Killing one Kang is not really a victory when another emerges from a different timeline, or more powerful variants of Kang like Immortus interfere in history.

Galactus

Galactus Reaching

Galactus is a truly powerful villain who can consume entire worlds. He needs to do so to sustain himself and would have destroyed the Earth if not for the intervention of the Silver Surfer, his herald at the time.

Galactus possesses cosmic awareness, the ability to transmute matter and convert energy on truly amazing scales, which he has done to transform beings into his heralds. He does this through the use of the Power Cosmic, which makes him one of the most powerful Marvel cosmic beings.

Molecule Man

Molecule Man surrounded in energy in Marvel Comics

Owen Reece, the Molecule Man, can manipulate molecules themselves, making him extremely powerful. Early in his confrontations with the Fantastic Four, this manifested in energy beams and force fields. As time went on, he was able to alter reality itself on a truly cosmic scale.

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In fact, Owen Reece isn't Owen Reece but a fragment of a being that exists throughout the multiverse in every reality. Every dimension has a fragment of this molecular entity, meaning that Molecule Man has agency throughout infinity.

The Beyonder

A giant image of the Beyonder appears over Earth as heroes rush to defend it in Marvel Comics.

The Beyonder is a cosmic entity who exists outside of all time and space, and even beyond all dimensions, giving him power out of the reach of even Molecule Man. The Beyonder can alter reality with a thought, and create and destroy universes at will.

He first appeared in the original Secret Wars #1 back in 1985 when he instantly teleported all of Earth's heroes and villains to a planet called Battleworld. The Beyonder later was able to defeat Galactus with virtually no effort.

Doctor Doom

Doctor Doom ruling over Battleworld in Secret Wars 2015 comic.

In Secret Wars, Doctor Doom briefly stole the power of The Beyonder. In the 2015 comic book event of the same name, Doom steals the power of all the Beyonders from the Beyond Realm and becomes God Emperor Doom.

In this form, he is the most powerful villain the Fantastic Four have ever faced and during his reign, the most powerful being in existence. He ripped out Thanos' skeleton with his bare hands and altered reality to make the Fantastic Four his team and family, displacing his hated rival, Reed Richards as the patriarch of the Fantastic Four.

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