In Avengers: Infinity War, the heroes of the Marvel Cinematic Universe are going to take on Thanos for the first time and it looks like it will be a fight that they might not actually be able to win. Thanos is putting together the Infinity Gauntlet and if he succeeds, that could be game over for the entire Marvel Cinematic Universe as we know it. From the trailers that we have seen so far, it looks like the movie Avengers are having more than a little difficulty with Thanos and his Black Order, even before he has actually put the Infinity Gauntlet together.

With their demonstrated difficulty with defeating Thanos and his minions, we thought it would be interesting to look at some other Marvel villains who the Movie Avengers would be severely constrained to be able to defeat. These villains are generally at least as powerful as Thanos. In fact, in a number of the instances, they are a great deal more powerful than Thanos... without the Infinity Gauntlet, that is; anyone with the Infinity Gauntlet becomes one of the most powerful beings in the universe. If the Avengers can't handle Thanos, they would be in deep trouble trying to take on these villains.

15 KORVAC

Michael Korvac was a human collaborator with the Badoon, the evil aliens who invaded the Earth in the alternate future that was the basis for Marvel's original Guardians of the Galaxy. The Badoon transformed him into a cyborg. The Grandmaster then brought him to the present to fight the Defenders. In doing so, he gave Korvac increased powers. Korvac then used those abilities to travel to the present himself.

Once there, he found a way to give himself the Power Cosmic. Now nearly a god, he seemingly decided to live a quiet life with Carina, the daughter of the Collector, but the Avengers and the Guardians couldn't trust that he had changed for good. They tracked him down and he felt compelled to fight back. He killed most of the heroes before he saw that Carina now doubted him, so he killed himself (reviving the heroes in the process).

14 GALACTUS

Galactus is a fascinating figure in the Marvel Universe because there is a debate over whether he is truly a villain or not. For instance, let's say that a hurricane comes through an era and destroys a town. Was the hurricane a "villain"? No, right, because the hurricane is just a force of nature. That's the common argument for Galactus.

Yes, when Galactus comes to an area, he literally devours worlds and thus kills many people, but such is his cosmic nature.

But is he just the cosmic equivalent of a hurricane? Different writers have had different takes on the concept. Some give him enough free will that he is still consciously killing billions on a regular basis. In either event, he's clearly one of the most powerful beings in the Marvel Universe, which is perhaps why his treatment in Fantastic Four: Rise of the Silver Surfer was derided for being so poorly executed.

13 VULCAN

In one of the worst things that he has ever done (and that's saying a lot), Professor X did not tell Cyclops and Havok that he had discovered their long-lost third sibling, Gabriel Summers. Gabriel helped lead a team of X-Men on an attempt to free the original X-Men after they were captured. This new team was slaughtered and Xavier just decided to wipe Cyclops' memory of the incident. Years later, when the Scarlet Witch released a wave of mutant energy after she essentially "erased" most of the mutants on Earth, the resultant release revived Gabriel.

Powered by roughly a million mutants, Vulcan was now possibly the most powerful mutant on Earth. He used this power to first seek out revenge on Xavier before turning his eye on the Shi'ar Empire (Gabriel's father was the former insane emperor of the Shi'ar). He quickly conquered the entire Shi'ar Empire before his inevitable fall.

12 MEPHISTO

Mephisto is a strange one in the Marvel Universe because, as he is essentially one of Marvel's versions of the devil, he typically tries to use his powers not aggressively but to instead seduce people into doing what he wants. Because of that, he rarely actually gets into a physical fight.

However, the power levels that Mephisto has shown have been so tremendous.

After all, he erased Spider-Man's very marriage from existence! The amount of magic needed to do something like that is crazy. With that in mind, it seems hard to believe that he wouldn't be able to take out the MCU Avengers if he wanted to do so. He just prefers to win souls through negotiating than attacking people with force. Plus, it is unlikely that he gets their souls if he just outright kills them himself.

11 ABRAXAS

In the Marvel Universe, there exists what you could call the "Cosmic McGuffin," which is a device that really only serves as a plot stimulator and not something that you would actually use. It is called the Ultimate Nullifier and since it can literally "nullify" the universe, even the mighty Galactus is afraid of it. One of the few times that the Ultimate Nullifier was actually used was when Abraxas showed up.

Abraxas is, essentially, the opposite of Galactus, and when Galactus was briefly destroyed a while back, Abraxas went on a rampage in not just the regular Marvel Universe, but in other universes, as well. His whole game was hunting down and killing different versions of Galactus. Eventually (we bet you thought we'd say ultimately), the Fantastic Four were forced to track down the Ultimate Nullifier and actually use it to re-form the universe without Abraxas in it.

10 CHTHON

While Mephisto is obviously the most famous example of the "devil" in the Marvel Universe, he is not the most powerful demon in it. That honor goes to Chthon, who was around in the days that Agamotto (of Eye of Agamotto fame) was an actual being in the universe!

Chthon is most famous for being the guy who wrote the most powerful book of evil in the Marvel Universe, the Darkhold.

As powerful as Chthon is, he is somewhat limited by having to possess people. That's how he often shows up in the Marvel Universe (here, he is possessing Quicksilver). One of his strongest rivals in the Marvel Universe is the Scarlet Witch, but because the Marvel Cinematic Universe version of the Scarlet Witch doesn't have actual magical powers, she wouldn't be able to do anything to him.

9 DARK PHOENIX

One of the most famous heel turns in the Marvel Universe occurred when Jean Grey's powers expanded into the Phoenix Force in the pages of X-Men. Calling herself the Phoenix, Jean was manipulated by the villainous Mastermind so that he could gain power within the Inner Circle of the Hellfire Club. However, his manipulations backfired when Jean's mind essentially "broke" and she became Dark Phoenix.

As Dark Phoenix, she literally destroyed an entire planet of billions of people (well, alien beings)! The Shi'ar Empire issued a death sentence on Dark Phoenix. The X-Men had managed to get her back to her Phoenix form briefly, but it was only a matter of time until she returned to her evil form, so she killed herself. Later, it was revealed that the Phoenix Force wasn't actually Jean Grey, so it was perhaps in the "just part of the universe" evil, like Galactus.

8 HUNGER

The Hunger is a difficult villain to compare to the others because he does not necessarily exist in this universe. You see, the Hunger is from another dimension and his whole deal is that he is like Galactus, only instead of devouring planets, he devours universes! Whenever someone in the universe puts together their reality's version of the Infinity Gauntlet, it sort of sets off an alarm for the Hunger.

He then tries to manipulate his way into creating a gateway to enter their reality... and devours it.

He tried to trick Galactus into thinking that the Infinity Gems might finally sate Galactus' hunger, but instead, it opened up a portal for Hunger. Thanos, though, luckily stepped in and closed down the gateway. Had he not done so, Hunger would have killed everyone.

7 MAD JIM JASPERS

Jim Jaspers was a character introduced in the pages of Dave Thorpe and Alan Davis' Captain Britain run in Marvel UK's Marvel Super-Heroes. Then Alan Moore took over the series and had Jaspers' brain get mutated. It gave him the ability to alter reality itself, but the sheer amount of power that he gained also drove him insane, hence the more common name for the character -- Mad Jim Jaspers.

Jaspers was a politician who was ardently anti-superhero because he wanted to clear the world for his own personal amusement. He created the powerful synthetic cyborg bent on superhero destruction known as The Fury. The Fury is practically unstoppable and it was just a simple use of Jaspers' immense powers. Of course, that backfired when the Fury tried to destroy him, as well!

6 ONSLAUGHT

onslaught

Charles Xavier is one of the most powerful telepaths in the world. During the "Fatal Attractions" storyline, he had to step in and shut down Magneto's mind to keep his old friend from tearing the Earth apart. This was after the world tried to build a force field to keep Magneto on his asteroid home. Magneto of course smashed through it, creating a gigantic electro magnetic pulse all over the world. When Xavier wiped Magneto's mind, it attached itself to Xavier's. It sort of hung there and clung to all the worst impulses in Xavier's mind (which Xavier has plenty of).

Those evil impulses formed into a being made out of pure psionic energy, encased in a special armor to give it physical form. The new being, calling itself Onslaught, threw Juggernaut halfway across New York State. He was only stopped by Earth's heroes sacrificing their bodies to absorb his energy.

5 MOLECULE MAN

Owen Reese as Molecule Man screams in terror

In the Marvel Universe, it is a good thing that every being that gets seemingly ultimate power then decides to restrict themselves, because otherwise, the universe would be destroyed once a week (as opposed to the current once a year standard). The Molecule Man was an early Fantastic Four villain who gained the ability to alter the molecules in anything, except for organic matter.

He once easily destroyed Captain America's shield, Iron Man's armor and Thor's hammer!

Later, that restriction was dropped but by that point, he had slowly tried to become a better person. When he wants to be a bad guy, he could do pretty much anything (he once easily destroyed Captain America's shield, Iron Man's armor and Thor's hammer). It was his powers that allowed the Marvel Multiverse to start over again after the ending of Secret Wars.

4 THE CHAOS KING

Amatsu-Mikaboshi was a Japanese demonic entity who decided to take advantage of the time that the Asgardians were in the midst of one of their semi-regular Ragnaroks and attack the Olympians, in the hopes of wiping out all of Earth's pantheon of gods while the Asgardians were out of the way. Amatsu-Mikaboshi came pretty far, but the Olympians were able to stop him (not before he killed Zeus, though).

Amatsu-Mikaboshi then slowly but surely set himself up as the Chaos King, wreaking havoc with the various gods in the universe by conquering hell itself! At that point, he could command an army of the dead, including Zeus! This puts him at extremely high levels of power. If he can kill Zeus and then take over hell itself, he can certainly kill the movie Avengers.

3 HYPERSTORM

Hyperstorm is from the future, where he was the son of Franklin Richards (one of the most powerful beings in the Marvel Universe) and Rachel Summers (a powerful telepath and telekinetic who was briefly the host for the Phoenix force). That union formed one of the most powerful beings in the universe. Jonathan Richards, Hyperstorm, had control over what he termed the "Supreme Power" and it allowed him to do essentially anything he wanted against the Fantastic Four.

In the end, the Fantastic Four teamed up with Galactus, who attacked Hyperstorm. Unfortunately (depending on who you talk to), Galactus fell into a dimensional portal with Hyperstorm and might have died. Since Galactus ultimately returned, Hyperstorm is probably out there somewhere still, just waiting for the next moment to strike!

2 AKHENATEN

Akhenatwn is a weird guy. He was an Egyptian pharaoh who lived in about 1300 BC, but then the Celestial Order decided to give him a lot more power so that he could recruit more members to the Celestial Order. The problem was that he instead started to use that newfound power to cut a bloody path throughout the universe.

His biggest weapon was known as the Heart of the Universe, possibly a more dangerous weapon than the Infinity Gauntlet itself!

Akhenaten ended up being the absolute ruler of time and space. As it turned out, though, Thanos was still able to go back in time and prevent Akhenaten from getting the Heart of the Universe, so that made him a whole lot easier to deal with as a rival.

1 SHUMA GORATH

Shuma-Gorath is sort of like the Marvel Universe answer to H.P. Lovecraft's Cthulhu, as it is an ancient, powerful and awfully nasty magical creature that ruled over Earth in the early years of the planet's existence. It was temporarily destroyed by the time-traveler Sise-Neg and then later, by the god known as Crom (the one that Conan was always worshiping).

It tried to get to Earth by accessing the Ancient One, the master of Doctor Strange, who the Sorcerer Supreme was forced to kill to keep Shuma-Gorath from entering this universe. Later, Doctor Strange even killed himself when he was starting to be transformed by Shuma-Gorath, as well. Luckily, someone resurrected Strange. Still, Shuma-Gorath is much more powerful than Mephisto, who we have established is no slouch himself.