The Marvel Cinematic Universe has done a commendable job in terms of character development, particularly with its main characters, as it adapted arcs and stories from Marvel Comics. Kevin Feige got this train rolling by ensuring solo movies were done first before getting teams such as the Avengers and the Guardians of the Galaxy together. However, there seems to be an emphasis on really nailing the main characters alone. When all this energy is placed on such primary faces, then your secondary ones tend to suffer in terms of how their characters grow and evolve.

RELATED: 15 Villains DC Movies Ruined

From the movies so far, it's obvious a lot of work needs to be done with these secondary characters because the supporting cast does play a big part in the grand scheme of things. Directors and screenwriters need to take note because these characters help build the foundation and deserve to be brought to life in a respectful and impactful manner, similar to the comics we read and love. A cinematic universe is only as strong as its weakest link, after all. With that said, CBR decided to take a deep look at 15 secondary characters we believe the MCU ruined.

SPOILER WARNING: Major spoilers ahead for several MCU movies.

15 QUICKSILVER

The MCU's Quicksilver needed to be highly remarkable, since Fox was using the character as well in its X-Men cinematic universe. Sadly, what transpired in the Age of Ultron movie was very much a disgrace to the speedster. At the behest of the studio, which doesn't own the rights to mutants, Joss Whedon altered Quicksilver's origins, making him and Scarlet Witch a couple of superpowered science experiments that joined Ultron's gang. Along with this retcon, his bland personality didn't set him off on the right foot.

Aaron Taylor-Johnson tried too hard to be arrogant and simply didn't fit the role. To top it off, there weren't any super-cool speed sequences to marvel at like his counterpart's which stole the show in two movies at Fox. As such, this version of Quicksilver felt like a diluted spin on the character.  When he eventually made his heroic shift as an Avenger, it felt rushed, making it hard to feel much of anything as he died saving Hawkeye.

14 WAR MACHINE

war-machine-injured

War Machine (James Rhodes) is more than a sidekick to Iron Man (Tony Stark). The comics have painted him as such, as seen in events like Civil War II, where he even tussled with Thanos. Basically, Rhodey is his own man and a force to be reckoned with in his own right. However, in the MCU, he was depicted as nothing more than Stark's lackey, and kin of a joke.

In Jon Favreau's first movie, he felt peripheral, with no real purpose other than to babysit Stark, while the second movie just gave him a suit and told him to be Iron Man's back-up! In Shane Black's Iron Man 3, he was then made into the Iron Patriot and basically repurposed as the government's muscle. Terrance Howard or Don Cheadle never came off as authoritative, and in the Civil War film, seeing him used as target practice and paralyzed felt like he had no value.

13 JANE FOSTER

Jane Foster has been more than just a love interest to Thor. She's self-assured and strong-willed but the MCU always kept her as a damsel in distress. Sure, she had a couple moments where she kicked ass but Natalie Portman's performance never registered to the point that she became essential to the franchise.

As a character, Jane has a ton of potential, as seen in Jason Aaron's recent comics where she was worthy of becoming the new Thor while battling cancer in her human form. One would expect that directors like Kenneth Branagh and Alan Taylor would have done more with her, especially after she met both of Thor's parents. She seemed set to be his queen at times, then at others, their Romeo and Juliet dynamic felt overly forced. If anything, this inconsistency got annoying, which is why there hasn't been much outrage over her absence in Thor: Ragnarok.

12 LADY SIF

Lady Sif Shield

Sif is one of Asgard's best warriors, and while the MCU gave us this in bits and pieces, we never got the sense of grandeur we see with her in the comics. She feels like a filler character on screen and it's probably down to Thor and Jane Foster's relationship. In fact, the only time she felt important was when she gifted the Collector an Infinity Stone.

Sif has been seen kicking ass and being her own woman, then at other times she can be spotted fawning over Thor like a school-girl. Many fans were hoping that their legendary romance would be given time on screen, especially with Natalie Portman not returning, but now it seems they're giving Valkyrie the role Sif could have filled. Jaimie Alexander even took the character to Agents of S.H.I.E.L.D. to get some traction but she never ends up resonating with audiences.

11 MANTIS

Mantis from Guardians of the Galaxy 2 film

The comics depicted Mantis, not just as an empath, but as one of the galaxy's deadliest fighters. However, when James Gunn brought the character to life in Guardians of the Galaxy Vol.2, she was watered down into a plot tool to trick the Guardians. What's worse is that she became the butt of many unsavory jokes. It was highly disconcerting how Gunn made her the victim of bullying from Drax, which didn't feel progressive at all for Marvel Studios.

The way Mantis accepted this abuse while laughing it off came was distasteful. The MCU tries to push strong female characters, but we're still at a loss as to why they would objectify and embarrass a female lead like this. It was such a backward step, making her a walking punch-line instead of a true warrior.

10 BATROC THE LEAPER

Batroc Winter Soldier

In the books, Batroc, while being a dangerous acrobat, is still viewed somewhat as comic relief. He usually goes toe-to-toe with Captain America and comes out on the losing end but when the MCU got UFC legend Georges St. Pierre to take on the role, fans were ecstatic. Rightfully so, because this meant a real martial artist was in the role; and when we saw him fight in Captain America: The Winter Soldier, he didn't disappoint.

However, this scene with Cap was way too brief and Batroc's impact fizzled out pretty quickly. There wasn't much about his escape and re-capture into S.H.I.E.L.D. custody, and it felt like the Russos built up this major opponent only to realize he took up too much screen time! What also hurt is that we didn't get a sense of his personality at all, giving the impression of a bland and generic mercenary.

9 MARIA HILL

Maria Hill

Maria Hill has had a profound presence in the comics, from Mark Millar's Civil War to the recent Pleasant Hill arc that involved Kobik and supervillains being housed in a secret penitentiary. She also helped push the space shield initiative with Carol Danvers in Secret Empire, further proving that she's just as big an influencer to S.H.I.E.L.D. as Nick Fury or Steve Rogers are. However, the MCU has made her so minimal that we sometimes forget she exists.

Hill came off as nothing more than Fury's secretary in The Avengers and The Winter Soldier movies, barely showing her worth as a dangerous and capable operative. She has helped shape much of the Marvel Comics universe; but on screen, Cobie Smulders, sadly enough, isn't given that much to do. Hopefully, in Avengers: Infinity War, she actually feels like a character with a purpose.

8 AMADEUS CHO

Amadeus Cho has been crucial to many Hulk stories over the last decade. He's one of Marvel's most intelligent sidekicks-cum-heroes and now, Amadeus is also the Totally Awesome Hulk! It's quite a fitting development for someone who has stood by Bruce Banner through thick and thin, really helping him when the chips were down. Cho's been more of a brother than a sidekick so fans wanted to see him in some form on the big screen.

Martin Starr played a random guy in a lab in The Incredible Hulk, who was later revealed in the novelization to be Amadeus. Firstly, Starr isn't Asian and secondly, he was just a dude holding a pizza. The MCU missed a great opportunity here to bring this popular boy genius to life. Helen Cho (his mother's name in the comics) was played by Claudia Kim in Age of Ultron so we're hoping they retcon things and do him justice.

7 THE LEADER

Samuel Stearns begins to become The Leader in The Incredible Hulk

In Louis Letterier's The Incredible Hulk, we got Bruce Banner (then played by Edward Norton) cutting loose and upgrading what Ang Lee did. The fight sequences were amazing, as seen in the epic throwdown with Abomination. However, at the movie's end, Samuel Sterns got infected due to his gamma-ray experiments and turned into the Leader. In the comics, he's one of Hulk's major villains so fans were excited to see how he'd be used in the future.

Well, we're still waiting. The Leader (played by Tim Blake Nelson) was teased, carted off and never used again. Maybe the MCU doesn't have a place for full-fledged Hulk villains at the moment, but for those wanting more Hulk-oriented stories, he's the perfect foil. Fans also want to see how Sterns moves from Letterier's goofy, awkward scientist to the maniacal villain that often wrecks Banner's life.

6 THE WARRIORS THREE

The Warriors Three are the watchdogs of Asgard and in the comics, they haven't just accompanied Thor as bodyguards on adventures, they've had some major ones of their own. We've seen how important they've been in events like Ragnarok and Siege. Heck, the biggest of the trio, Volstagg, now wields Ultimate Mjolnir in the books and has become his own version of Thor! However, in the MCU, it seems that they're more of an entourage.

Fans have only glimpsed how important they are to the wars that Thor fights across the realms. They, like Sif, deserve more screen time because they've been the more disciplined, militant arm who defends Asgard while Thor goes about his many journeys of self-discovery. Other than helping him escape with Loki in Thor: The Dark World, they've felt like nothing more but decorative pieces in the Odinson's cinematic escapades, with only Volstagg getting some prominence in dealing with the Collector.

5 SHARON CHARTER

Steve Rogers and Sharon Carter in Captain America: Civil War.

Sharon Carter, aka Agent 13, has been alongside Steve Rogers for many modern comic events. She's seen as his true love and went through being brainwashed to kill him in Civil War, not to mention watching an evil version of the character nearly destroy the world in Secret Empire. It's pretty clear she's essential to his lore, yet for some reason the MCU spent a lot of time developing her aunt, Peggy, and kind of left Sharon in a (thus-far) minimal role.

In The Winter Soldier and Civil War movies, she was more of a supporting character than someone who fought with Steve as an equal. We're hoping this gets rectified soon because we'd love to see their romance spread and Sharon become important like in the Secret Avengers comics. So far, Emily VanCamp's character feels forced in just for the sake of having her.

4 DANIEL DRUMM

Daniel Drumm is integral to the Brother Voodoo mythos in the supernatural arena of Marvel Comics. Daniel's ghost remained part of his brother Jericho's life and in their adventures, they often found themselves fending off just as many heroes as they did villains. Daniel has taken darker routes as well, becoming an enemy of the Avengers, while his brother went on to become the Sorcerer Supreme. However, in the Doctor Strange film, Daniel was a mystical warrior in New York that was killed just as quickly as he appeared.

In the Sanctum Sanctorum, he tried to help Strange only to be killed by Kaecilius. What sucked was that Daniel wasn't really acknowledged, which would have been a great way to hint at a potential arc for Jericho. As it stands, Daniel was merely another generic warrior fighting evil, so hopefully the MCU does a better job with his brother.

3 SPIDEY'S MJ

Spider-Man: Homecoming really flipped the Spidey mythos on its head. After the character was brought into the MCU in Civil War, his origins wasn't touched on much, but you could tell it was a drastic reinterpretation from what Sam Raimi and Marc Webb did with their franchises. This reboot focused on a much younger version of the character in high school and while it dealt with the Homecoming dance, it wasn't really centered on romance. There was no Gwen Stacy or Mary Jane. Or so we thought...

Zendaya's Michelle revealed her nickname at the end to be "MJ," which really polarized fans. If this really is Mary Jane Watson, or some interpretation of her, we have no issue with the race change ,but they should give her iconic characteristics. Michelle's rebellious personality, while infinitely entertaining, just isn't the MJ we know and love. But who knows, maybe that's a good thing.

2 GENERAL ROSS

thunderbolt-ross-casting-black-panther

Thaddeus Ross is a bullish character in the life of one Bruce Banner. In the comics, his vitriolic hatred of the Hulk -- in some part due to how much his daughter Betty loves Bruce -- is undying. He even became the Red Hulk and was part of the Thunderbolts, just to garner enough power to kill the Hulk. On screen, Ang Lee's Ross was pretty good and in the MCU, Louis Letterier had William Hurt also give an impressive take on the relentless character.

However, when Hurt reprised the role in Civil War, he went from a rogue and ruthless general to a G-Man relaying orders. He was charged with implementing the Sokovia Accords for superhuman registration but instead, came off like Iron Man's annoying boss. Ross shouldn't play by the rules, so to see him domesticated like this was disappointing, as this version of him doesn't even seem like he could even wage a proper war against the Hulk.

1 AUNT MAY

The MCU really swung for the fences in rebooting the Spider-Man franchise. In Civil War, we no longer had the older version of Aunt May but instead, we were treated to a smoking hot middle-aged Marisa Tomei as the character. This got tough to digest, especially after the uncomfortable scenes of Tony Stark hitting on her. These jokes persisted in Homecoming and it was clear the MCU lost the essence of what Aunt May represented.

Making the character appeal to modern audiences is one thing but having her get hit on incessantly, then cutting out the Uncle Ben dynamic she had, just felt like key elements of Peter Parker's family were gone. Aunt May is an integral pillar in Peter's life, not just a bit of eye candy in the background. We loved what Tomei was able to bring to the role -- a palpable sense of understanding and heart -- but she could have been, should have been so much more.

Which other secondary characters do you want to see the MCU do justice? Let us know in the comments!