The upcoming “Avengers: Infinity War" promises to be the biggest Avengers movie yet, and given the potentially universe-destroying stakes involved, could cause some big changes in the Marvel Cinematic Universe status quo. We know Thanos will be its villain, as Marvel has been building him up since the first “Avengers” back in 2012, but he probably won’t be the only one. As the name suggests, the story is bigger than that, and is set to take up two movies (even if what Marvel has said is true, and one isn't a "direct sequel" of the other).

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With that in mind, what happens after “Infinity War"? It doesn’t seem possible to go any bigger than the Infinity Gauntlet, so whatever enemy “The Avengers” chooses for its sequel will probably have to offer a different direction. Perhaps at that point, the movies could even spend more time making its villains as compelling as its heroes, in order to finally overcome Marvel’s increasingly glaring villain problem. Whatever direction the future Avengers go in, there’s a wealth of great villains to choose from. For your consideration, we’ve rounded up our top 15.

15 Onslaught

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Wait! Come back! Yes, Onslaught is the focal point of one of the worst Marvel events ever. And yes, chances are that identity is owned by a more mutant-heavy film studio. But hear us out. Originally, Onslaught was an entity created from Magneto and Charles Xavier’s negative psionic energy. Through a complicated series of events involving Fantastic Four child / human plot device, Franklin Richards, Onslaught becomes an all powerful entity who it takes the entire Marvel universe to stop (almost).

That’s the in-comics story. The real story is that in 1996, Marvel Comics was going bankrupt, and was using Onslaught to make some money back via the “Heroes Reborn” storyline. After all of Marvel’s highest profile heroes seemingly die in order to defeat the villain, they’re transported to an alternate universe… drawn by '90s star artists Rob Liefeld and Jim Lee. Yes, Marvel effectively rented out The Avengers and Fantastic Four for a year to make money.

So here's why Onslaught (whose origin could easily be altered to come from MCU characters instead of X-Men ones) could work in movies. Robert Downey Jr.’s contract isn’t going to last forever. The cast of MCU will have to change eventually. What better way to do it than moving to an alternate universe?

14 Grim Reaper

Grim Reaper shows off his scythe hand in a Marvel comic

While it’s not clear exactly what his role will be beyond “being Nathan Fillion,” Wonder Man is coming to the MCU in “Guardians of the Galaxy Vol. 2,” which means his brother may be soon to follow. Eric Williams grew up as the black sheep of the Williams family, jealous of his older brother Simon. After Simon becomes Wonder Man and goes from villain to hero, who sacrifices his life to save the Avengers, Eric blames the team, and is given his signature scythe by another great villain, the Tinkerer.

With his classic look and name, The Grim Reaper would be a great addition to any superhero movie. While he isn’t quite big enough to be the main villain, his complex relationships with many different Avengers characters would make him a rich supporting character. His strange dealings with Ultron, who views him as “family” and has enhanced his powers, and his relationship with his brother, which has seen him both fight against and work with one of the strongest Avengers, could recall the best of the “Avengers” films’ current best villain, Loki.

13 Lord Templar/The Triune Understanding

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The Triune Understanding is one of the weirder foes Earth’s Mightiest Heroes have faced. First seen in Kurt Busiek’s classic late ‘90s/early ’00s “Avengers” run, the Triune Understanding is a religious movement and/or cult that claims to maximize human potential, led by a man named Jonathan Tremont. It turns out their real goal, unbeknownst to its members, is to stop an alien threat called the Triple Evil. This, as you might imagine, is a deep concept, and one which contains a ton to work with along the way.

The Understanding has its own superhero, Triathlon, who has three times the physical ability of normal humans at their peak, and is connected to 3-D man, an older hero with similar powers. Triathlon is basically foisted onto the Avengers by the government when Tremont attacks them for religious intolerance against his group. As both heroes are black, they could, on a very functional and necessary level, add some much needed diversity to the team. The craziest thing about the inclusion of these characters, however, is the endgame. The real mission of the Triune Understanding is to use its believers to power a faith-fueled spaceship that projects a massive, solid hologram that fights alongside Tremont’s cosmic-powered brother, Lord Templar (who will then take over Earth). In practice though, the plan achieves something else: Giant Cap!

12 The Masters of Evil

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There have been at least nine different teams called The Masters of Evil over the years, including one lead by Baron Heinrich Zemo, and a different one led by Baron Helmut Zemo. The members of the team may be less important than the fact that it’s a team. The clear highlight of “Captain America: Civil War” was the insanity of the airport battle between teams of superheroes. Imagine if, instead of a battle between friends trying not to hurt each other, that battle had actual stakes between two equal but opposing forces!

There are a million ways the MCU could go with this: Ultron’s Masters of Evil would bring back the “Age of Ultron” villain, the younger Zemo could come back to life with his crew of over a dozen people, or you could even have the team that would eventually become the Thunderbolts. The Avengers are now established enough that there’s definitely room to introduce and develop a team of evil counterparts. If Marvel’s feeling real adventurous (or people start to get tired of the formula), they could even do it “The Superior Foes of Spider-Man”-style, and make the Masters of Evil the main characters, for a change of pace.

11 Taskmaster

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Not much is known about the very comic book-y named Tony Masters, but his powers are actually as cool as he looks. An amoral mercenary, The Taskmaster has “photographic reflexes,” a form of photographic memory that gives him the ability to perfectly mimic the physical movements of anyone he witnesses, including members of the Avengers. Rather than trying to fulfill any specific villainous goal or personal vendetta, Taskmaster begins his career by stealing enough money to start a training center for aspiring professional criminals.

With his combination of extremely entertaining skills and and serious hustle, Taskmaster is a somewhat unusual villain. Over time, he’s posed as Captain America, worked for the above-mentioned Triune Understanding, been hired by the government, fought Daredevil and the Punisher in a contest, joined the Thunderbolts, and infiltrated S.H.I.E.L.D. in order to test its security. He could work as a big bad -- just imagine a skull-faced guy in a hat emulating Cap and Black Widow’s every move in a fight -- but he could also be the kind of side-element whose existence evokes that of a larger world. Don't forget, he’s trained characters ranging from the “Winter Soldier”-villain Crossbones, to Spider-Woman, an Avenger herself.

10 Sin

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However much you may have liked him as The Red Skull in “Captain America: The First Avenger,” Hugo Weaving is definitely not coming back. The villain’s daughter Sin, on the other hand, is available... and may be a way better option anyway.

Even for the daughter of a supervillain whose head is a literal red skull, her backstory is pretty bizarre. After fathering her with a washerwoman hoping for an heir, he nearly kills the baby, Sinthea Schmidt, when he sees she’s not male. Luckily (or not, as the case may be), he's stopped by his follower, Mother Night, who raises and indoctrinates her. Later, Sin's father ages her into adulthood with a strength-enhancing machine, and she becomes Mother Superior, who leads a group of machine-enhanced children called the”Sisters of Sin." Eventually, she's restored by S.H.I.E.L.D. to her original age, with her memory wiped... until Crossbones restores them.

In addition to doubling the total female villains in the MCU (is Nebula it?), Sin could seek revenge on Cap, maybe by leading the kind of Masters of Evil team mentioned above. Alternatively, depending on how "Thor: Ragnarok" goes, we could see a cinematic version of "Fear Itself," which could be interesting. Plus, since her age is always changing, she could even give the Avengers their first teenage girl villain, which would definitely be a change of pace.

9 M.O.D.O.K.

The Marvel Comics villain M.O.D.O.K. strikes a threatening pose.

Just look at M.O.D.O.K. for a second -- how could you not want him in a movie? If that wasn’t enough, the name is an acronym for: “Mental/Mobile/Mechanized Organism Designed Only for Killing.” M.O.D.O.K. began life as George Tarleton, a technician for Hydra-counterpart A.I.M., who was subject to mutagenic experimentation meant to create a super intelligent computer. (Un)Fortunately, it ends up turning him into a killer who takes over the organization.

M.O.D.O.K. is one of those classic Marvel villains who’s not quite big enough for the A-list, but always such a fun time that you’re glad whenever he pops up. It’s characters like M.O.D.O.K. that make the Marvel Universe feel like a place filled with real people (and robots), not just marquee names. That is exactly why he could be a perfect secondary villain, similar to our Taskmaster idea; leading a faction caught up in a greater battle. If the movies wanted to go smaller scale for a change, couldn’t you see him as the big bad, trapping the Avengers in a maze or something equally as ridiculous? Either way, M.O.D.O.K. is potentially both one of the funniest villains the Avengers could face, and the most unnerving. Seriously, look at him!

8 Squadron Supreme/Sinister

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We already mentioned how the Avengers could go up against a whole team, but The Masters of Evil isn't the only one available. There’s also the Squadron Supreme and Squadron Sinister. The first is an Avengers-like team of superheroes from an alternate universe; led by the extremely powerful Hyperion, the team was in reality based on the Justice League. In one iteration, the Squadron’s universe is destroyed, and they end up on main Marvel world Earth-616, where they’re tricked into fighting the Avengers; not because of mind control, but because they believe the Avengers are impostors.

With the potential of “Infinity War” to destroy universes and permanently alter the status quo, a follow-up that centers around a team from a destroyed universe could humanize the fallout from the perspective of non-Avengers. If you want to get real team-y, it could also involve the Squadron Sinister, an evil team modeled after the Squadron Supreme, only they’re... y’know, evil. In fact, the groundwork for that is already being laid: they were created by the villain Grandmaster, who will be played by Jeff Goldbum in “Thor: Ragnarok” next year.

7 Hela

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Speaking of “Thor: Ragnarok,” you may know that Hela, portrayed by Cate Blanchett (!), is already set to be a villain in that movie too. But so far, bringing a villain from a Thor movie into the Avengers franchise has already resulted in Marvel Studio’s most successful villain so far. Based on the mythological Norse goddess Hel, Hela has another one of those extremely comics backstories: she’s the daughter of a giantess and a previous incarnation of Loki, who died during a previous Ragnarok, and was appointed the Goddess of Death by Odin.

The ruler of the realms of Hel and Niffleheim, Hela is caught up in the same dramatic Asgardian drama as Thor and Loki, and is stronger than both. Actually, until Thanos finally shows up, she could be the strongest villain in the MCU (if you leave out Dormammu’s two minute appearance in “Doctor Strange”). Hela is already adding some much-needed female villainy to Marvel’s films, so letting her character grow over multiple movies seems like a win-win. Whether rumors that she’ll appear in “Infinity War” are true or not, there’s no reason not to put Cate Blanchett in three flicks, right?

6 The Skrulls

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The Skrulls are an empire of shapeshifting aliens who first appearing in “Fantastic Four” #2 in 1962, making them older than most Marvel characters. The first “Avengers” movie had to use their Ultimate universe counterpart -- the Chitauri -- because Marvel doesn’t currently have their film rights. Saying that, it may be worth getting them (especially as wild rumors continue to abound that the "FF" franchise may revert back to Marvel a-la Spidey), because the Skrulls offer a ton of unique story possibilities.

The go-to story would probably be “Secret Invasion,” which began with the revelation that many key people on Earth had years ago been replaced with Skrull impostors. After the biggest possible battle against an external evil in “Infinity War,” the best follow up may be to go in the opposite direction, placing the enemy within. A story based on “Secret Invasion” could take the paranoia of “Winter Soldier” to the next level, as the celebration of the Avengers' greatest victory quickly becomes sown with doubt. Add the Super-Skrull -- a sort of Skrull superhero who can wield the abilities of its enemies -- and you get an Avengers movie like none before it.

5 The Supreme Intelligence

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A giant floating head who evokes Zordon from “Power Rangers,” the Supreme Intelligence isn’t exactly a villain. A million-year old being created by an alien race called the Kree, the Supreme Intelligence was originally a computer that assimilated the minds of all the greatest Kree thinkers, which then developed a mind of its own. Its mission is to keep the Kree evolving, which it does both as the race’s godlike leader, and through manipulating the galaxy with its mental and physical strength.

With an unparalleled mind and powerful psionic abilities, which include (but are not limited to) telepathy, precognition, telekinesis and the ability to manipulate nearby reality itself, the Supreme Intelligence has earned its honorific title, Supremor. As the Kree are intricately connected to the Avengers, especially the soon-to-make-her-film debut Captain Marvel, it may even appear sooner rather than later. Whether it’s as part of the Kree-Skrull War, in a power struggle with a resurrected Ronan the Accuser, or something else entirely, it’ll make a compelling foe.

4 The Beyonder

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Before Jonathan Hickman’s massive “Secret Wars” event, there was Marvel’s original “Secret Wars." The Beyonder is “the sum total of a multiverse,” the energy of a pocket dimension which gains sentience, and eventually decides to take the form of an extremely ’80s-looking man. In “Secret Wars,” the Beyonder creates a planet called Battleworld, and kidnaps many of Marvel's superheroes and villains, making them fight so that he can observe the battle between good and evil up close. In the less-well-received “Secret Wars II,” the Beyonder takes a stylistically disastrous human form, both learning more about humanity and nearly destroying the universe.

Pitting the characters of the MCU against each other wouldn’t just have to mean heroes vs villains; as has been popular in the books recently, heroes vs heroes seems to be all the rage. This could even be integrated with a Squadron Supreme plotline. Hell, if we’re going really nuts, why stop at Marvel? The Beyonder could even pull in the Fox-owned X-Men movies too, for the first step towards making Patton Oswalt’s dream a reality. Sure, it sounds impossible, but it wasn’t that long ago that the idea of a "Guardians of The Galaxy" movie seemed ridiculous, let alone *two* of them. So who knows!?

3 Mephisto

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Essentially Marvel’s version of the devil, Mephisto is somehow one of the oldest, most powerful, and most mysterious villains the Avengers have ever faced. Since he’s really just Satan, his origin can be shaped into whatever will best fit into the MCU. Also, since he’s existed since, apparently, the beginning of time, he can be inserted into the background of MCU history the same way Hydra was, only even more so. Much of the groundwork is already there: as the ruler of his own Hell-like dimension, he’s made deals with Hela, and in Jim Starlin’s “Infinity Gauntlet” (the story “Infinity War” is based on), he acts as Thanos’ lieutenant, hoping to manipulate the Titan’s power for his own benefit, so he may appear sooner.

Mephisto is also connected to many heroes who have made it to the screen: he gave Ghost Rider his powers, and, in a less well-received plotline, retcons Peter Parker and Mary Jane’s marriage out of existence in exchange for saving Aunt May. While those specific versions won’t make it to the Avengers, the core idea has potential. After the destruction of “Infinity War,” what Avenger wouldn’t consider a deal with the devil to prevent another?

2 Morgan Le Fay

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The Avengers already have plenty of Norse mythology in the mix, but as of yet, there are none from Arthurian legend. That could change with the introduction of Morgan Le Fay, the half-faerie half-sister of King Arthur. If “Ragnarok” does see the destruction of Asgard, the mystical, sixth century England of Morgan Le Fay’s birth could fill some of the mythological void, and her Celtic magic and roots could give her a connection to the MCU’s “Celtic” version of The Ancient One.

A nemesis of Black Knight, an Avenger who wields Excalibur, Morgan Le Fay has fought many of Marvel’s heroes over the centuries. Trained by Merlin in sorcery, and wielding psychic and mystical powers granted by her Faerie heritage, she's difficult to defeat in battle, but her biggest attack on the Avengers is a different kind. With the aid of an Asgardian weapon called the Twilight Sword, she kidnaps the Scarlet Witch, and uses her power to remake reality into a Medieval world where she is ruler, and the Avengers are her knight-esque servants. She's been onscreen before, played by Jessica Walter in the bizarre 1978 Doctor Strange TV movie; of course, we think it's time for a more modern attempt.

1 Kang The Conqueror

Kang the Conqueror

After Loki and Ultron, Kang The Conqueror is probably the most well-known and consistently troublesome Avengers villain, and he may be the best. A scholar born in the 30th century, Nathaniel Richards is bored by the utopian society of the future, so he travels back in time to ancient Egypt, where he becomes the Pharoah Rama-Tut, in his first taste of conquering. He’s defeated by the Fantastic Four, but then winds up in the 40th century, where he resumes his conquering. After the Avengers stop him there, he returns to his home century, which he also conquers. Kang is nothing if not repetitive.

Unlike the rest of the Avengers' classic foes, Kang has no superpowers beyond what his technology and genius give him; he’s just very good at conquering. Marvel’s 20th and now 21st centuries, though, always seems to thwart him, which leads Kang into some very bizarre personal entanglements with various Avengers, including a wild time travel-based battle with his future self, Immortus, that unfolds in "Avengers Forever." But the simplest version is that Kang is a man so into conquering that he can’t just conquer universes, but has to take them over in multiple different eras. If nothing else, that is definitely worthy of an "Avengers" movie.

Who would you like to see the Avengers battle post-"Infinity War"? Let us know in the comments!