Avengers: Endgame delivered a satisfying finality to a slew of stories from the past 11 years. But it also brought with it a lot of changes that will start to become apparent with the beginning of Phase 4 of the Marvel Cinematic Universe. One of the most significant conclusions was Steve Rogers' retirement. The Avenger went back in time and lived out his life, so now he is far too old to be Captain America. That brought with it a game-changing decision.

To pass on the mantle of Captain America to his good friend Sam Wilson, shield and all. Phase 4 and the Falcon and Winter Soldier series will have to tackle how the former pararescue will come to terms with this new heroic responsibility. But a hero is not a hero if there's no villain to stand in the way. With that said, here are the 10 villains we want to see Falcon face as Captain America.

RELATED: 10 Reasons Why Falcon Should Be The New Cap In The MCU (And 10 Reasons Why Bucky Should Take The Shield)

10 10. M.O.D.O.K

M.O.D.O.K is an... interesting character. His origins as a technician turned lab rat, resulting in a process that made him exceptionally intelligent, powerful, and insane, are actually a perfect fit for the introduction of a new MCU villain. However, there is the slight problem of him taking the form of a giant floating head, something understandably ridiculous for the big screen. This doesn't mean that there is no chance we'll see him, though.

Since 2011, Christopher Markus (one of the screenwriters for all Captain America movies, plus Infinity War and Endgame) has stated his desire to see the giant head on the big screen. The truth is, as weird as he is, M.O.D.O.K remains one of Captain America's biggest foes, so seeing Sam Wilson don the costume against the evil floating body would only make sense.

9 9. Taskmaster

Taskmaster is not quite a villain, but he's definitely not a hero. Tony Masters was born with what is referred to as photographic reflexes. This means he can replicate any person's movements by just observing them. With this ability, he decided to open a base of operations to train anyone to fight, regardless of their intentions. This means he ended up training a bunch of villains, including tons of Hydra agents.

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He also works as a mercenary, always working for the highest bidder. While he has been on the heroes' side, the bad guys are usually the ones who seek his services. He has fought the Avengers, and especially Steve Rogers, quite a few times, and this is a character that could be one of the most interesting grounded villains in the MCU. One that could fit perfectly into the Falcon and Winter Soldier series?

8 8. Batroc The Leaper

Marvel Studios has shown a strangely consistent habit of undermining great Captain America villains. Except for Hydra and Red Skull, enemies like Crossbones, Zola, and Strucker were all shunted to the sidelines, despite their huge influence in the comics. Maybe the only major Cap villain who is still alive is Batroc the Leaper. After a very brief fight with Steve Rogers at the beginning of Winter Soldier, he was then captured by SHIELD/HYDRA and was never seen again.

For Sam Wilson's first showdown as the star-spangled Avenger, it would make sense to bring back one of Steve's forgotten foes. Red Skull might be too high-profile, but Batroc is a deadly, yet non-superpowered opponent, just like Falcon, that would provide a decent first battle and establish a direct connection between Steve Roger's past and Sam Wilson's future.

7 7. Galactus

If anyone can challenge Thanos for the title of biggest intergalactic threat in the Marvel universe, it's the literal consumer of planets, Galactus. With the Fox properties moving to Marvel Studios, this is now a possibility for the next saga. As one can imagine, Galactus doesn't necessarily hold a particular grudge against Captain America, but just like with Thanos in Endgame, it was immensely satisfying seeing the star-spangled Avenger hammer (literally) the Mad Titan.

We can only imagine that we will spend a considerable amount of time with Sam Wilson as a main MCU protagonist, to the point where he might be among those who lead the attack, along with the entire Marvel Cinematic Universe, against Galactus in the next Avengers: Endgame. How exactly they would defeat a being the size of several planets is beyond me...

6 6. Scarlet Witch

Before anyone starts complaining, there is no evidence that this may happen, but based on her comic book counterpart, it is a possibility. Wanda Maximoff is both hero and Avenger, that is true. But let's not forget her evil, traumatic beginnings, her immense, untapped potential, and the fact she is still grieving the loss of Vision and of her brother. We all saw how her rage alone was nearly enough to kill Thanos in Endgame.

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The comics basically took a step further with House of M, where they decided to test what would happen if all this tipped her over the edge into villainous waters. With Steve Rogers no longer an Avenger, Natasha Romanoff dead, and Clint Barton retired, Sam Wilson is definitely Wanda's closest friend. If Scarlet Witch were to turn against the Avengers, her battle with Falcon would be the most tragic.

5 5. Hydra Cap

In 2016, Marvel released a comic book with one of the most controversial plot twists in the history of comics. The last panel of Captain America: Steve Rogers saw the Avenger presumably revealing his true alliance, as he uttered the words "Hail Hydra". However, it was later revealed to be an alternate Cap, and not the original, noble hero. One who fought the Avengers, including a Captain America-suited Sam Wilson, and was then apprehended and locked away.

In the MCU, we've seen Steve fight his close friends, including Tony Stark and even Bucky Barnes, but he's never laid a finger on Falcon. Endgame introduced us to alternate universes (with even the Far From Home trailer referencing a potential multiverse), so potentially seeing a future fight between an evil Steve Rogers and a conflicted Sam Wilson would be an awesome way to test this new Captain America.

4 4. U.S Agent

Once again we have a character who is much more friend than foe. While Wanda Maximoff did have a slight super-villain phase, John Walker's government position is what provides the occasional thorn in the Avengers' side. Basically, the MCU's General Ross, if he also had a vibranium shield and punched bad guys. On one particular case, U.S. Agent went toe to toe with Sam Wilson.

This was due to the fact that Falcon had been given the title of Captain America after Steve Rogers' death but was deemed unworthy of it by some. John Walker was among these and actually tried to force Wilson to hand over the shield. The reaction to Sam Wilson becoming the new Cap is an interesting approach that Marvel Studios could take, and they might as well include U.S. Agent as a physical obstacle.

3 3. Thunderbolts

With 22 movies under their belt, and the incredible moments in Infinity War and Endgame that a Marvel fan could only dream of witnessing in a movie theatre, it might seem as if there's not much they can do to hype the MCU up even more. Fortunately, we still haven't been given something fans have been clamoring for a long time, that even the DCEU has begun to do. A super-villain team-up.

RELATED: Does Ant-Man and The Wasp Set Up a Thunderbolts Film?

Fortunately again, rumors are swirling regarding a future Thunderbolts movie, that would include the likes of Red Skull, Zemo, General Ross, and Justin Hammer, among others. We mustn't forget that Sam Wilson is now officially one of, if not the main Avenger, after becoming Captain America. So if this terrible team-up were to happen, the ex-Falcon would be on the frontlines of the eventual battle Earth's Mightiest Heroes and the world's greatest threats.

2 2. Doctor Doom

Galactus was mentioned as a possible "greatest threat in the universe" for the next batch of movies, but there is no other villain like Doctor Doom. He may be human, but he has one of the world's most intelligent scientific minds, was trained in various martial arts in Tibet, and is one of the most powerful sorcerers alive.

In addition to that, he is also the king of Latveria, and enjoys diplomatic immunity, meaning no one can touch him in his country, or in the Latverian Embassies. He is basically what happens if you put Iron Man, Batman, Doctor Strange, and Black Panther together and add a bucket of pure evil to the mix. This is a major villain, one that would force Sam Wilson to lead every hero available into battle.

1 1. Red Skull

Regarding the MCU villains that may return in the future, there is none more intriguing than the possibility of seeing the Red Skull back in action. After his surprise appearance in Infinity War (and once again in Endgame), he is now free of his duty as Keeper of the Soul Stone, meaning he can leave Vormir and pursue other objectives. Then let's not forget that Red Skull is, and always has been, Captain America's number one foe.

Johann Schmidt has been a thorn in Steve Rogers' side since his appearance in the first ever Captain America comic book in 1940. In the MCU, he was also the first villain the super-soldier faced. Round one was a battle between two still inexperienced foes in the 1940s. It would only be fitting that round 2 saw a wise, and more powerful Red Skull face a military trained, new and improved Captain America in the form of Sam Wilson.

NEXT: How Endgame Sets Up the Falcon & Winter Soldier TV Series