Marvel Studios' Marvel Cinematic Universe doesn't look much like Marvel's comic book universe. Without major teams like the X-Men or the Fantastic Four and villains like Dr. Doom or Galactus, the MCU is missing some big parts of the regular Marvel Universe. Combined with the logistical restrictions of creating a live-action version of their world for a wide audience, this has created a perfect situation to give some unexpected characters a spotlight. Now, one of the MCU's hallmarks is how it takes obscure heroes, villains and supporting characters from the depths of Marvel's back issues and re-envisions them as major players onscreen. Even generic characters who only made one or two comic book appearances have become key cast members of major motion pictures.

RELATED: 15 Major Marvel Characters Completely Cut From Movies

Now, CBR counts down minor Marvel characters who played major roles in the Marvel Cinematic Universe. For this list, we'll be looking back at how historically less important characters rose to take on headlining roles in Marvel's movies and shows. While we won't be including original characters with prominent parts in the MCU, like Clark Gregg's S.H.I.E.L.D. Agent Phil Coulson, we'll also be looking at the bold re-imaginings that turned these obscure heroes and villains into movie stars.

16 GUARDIANS OF THE GALAXY

Guardians of the Galaxy team

Before James Gunn's Guardians of the Galaxy hit theaters in 2014, Star-Lord, Gamora and the rest of Marvel's most famous cosmic team were footnotes in the Marvel Universe. While the Guardians had scattered introductions and supporting roles across Marvel's titles over the years, Dan Abnett, Andy Lanning and Paul Pelletier officially brought them together in the wake of the 2008 crossover Annihilation Conquest. While their early adventures received rave reviews, the Guardians were still largely relegated to the isolated cosmic corners of the Marvel Universe.

Despite the Guardians' relative obscurity, their irreverent cinematic debut was a critical and commercial blockbuster. Even though they were still isolated from the MCU's earthbound heroes, the movie reset the trajectory of the MCU with its fun cosmic adventure and charming cast. Since that film's success, the Guardians have taken on a more central, well-connected role in Marvel's ongoing comic sagas.

15 PEGGY CARTER

Peggy Carter Haley Atwell

In the Marvel Cinematic Universe, Hayley Atwell's Peggy Carter was Captain America's wartime love and became a key figure in the universe's 20th century history. In Joe Johnston's 2011 film, Captain America: The First Avenger, Carter fell in love with Steve Rogers while battling the Red Skull and Hydra during World War II. While Rogers was sleeping in the Atlantic, she helped co-found S.H.I.E.L.D. and carried on the good fight over two seasons of her own series, Agent Carter.

Although Captain America first appeared in the 1940s, Peggy Carter didn't debut until 1966's Tales of Suspense #77, by Stan Lee and Jack Kirby. While she retroactively became part of Captain America's wartime history, Sharon Carter, her niece, has historically been Rogers' more prominent comics love interest. Before her death in 2011's Captain America #1, by Ed Brubaker and Steve McNiven, Peggy used to go for years without making an appearance.

14 VULTURE

Vulture Michael Keaton

Michael Keaton's Vulture was one of the many highlights of Jon Watt's Spider-Man: Homecoming. In the 2017 film, Adrian Toomes was re-envisioned as a formidable high-tech scavenger who created weapons based on alien technology. With a well-conceived origin rooted in the destruction of 2012's The Avengers, he was a formidable antagonist for Spider-Man's first solo outing in the Marvel Cinematic Universe.

While he became one of Spider-Man's first villains in 1963's Amazing Spider-Man #2, by Stan Lee and Steve Ditko, the Vulture has never been Spider-Man's most lethal foe. In a world full of goblins and hunters, an old man in a flying harness doesn't inspire a great deal of fear. That hasn't kept Toomes from battling Spider-Man on multiple occasions, usually with the Sinister Six. Even after some recent power boosts, the Vulture still can't fly as high as Spider-Man's most famous villains.

13 CLAIRE TEMPLE

Claire Temple Rosario Dawson

In the same way that Agent Coulson tied Marvel's first movies together, Rosario Dawson's nurse Claire Temple has tied Marvel's Netflix shows together. As the link between Daredevil, Jessica Jones, Luke Cage and Iron Fist, Temple played a key role in bringing Marvel's street-level heroes together to form The Defenders. In a role inspired by Marvel's Night Nurse, she also serves as the superheroes' main doctor too.

Long before Jessica Jones, Claire Temple used to be Luke Cage's main love interest. Created by Archie Goodwin and George Tuska in 1972's Luke Cage, Hero for Hire #2, Temple dated Cage throughout the 1970s. Like her MCU counterpart, Temple was a nurse, and she had a nasty habit of getting kidnapped. After an appearance in 1983's Power Man and Iron Fist #100, Temple vanished for 33 years, until she reappeared in the wake of the Netflix shows.

12 ANT-MAN

Ant Man Paul Rudd

Since he was created by David Michelinie and John Byrne in 1979's Avengers #181, Scott Lang hasn't had the most illustrious career in comics. Even though he became the second Ant-Man and an Avenger, Lang never eclipsed the first Ant-Man, Hank Pym. Since he wasn't able to hold down his own title for too long, Lang became a perennial supporting character in titles like Iron Man and Fantastic Four.

Since Pym's complex, controversial history of mental instability made him an integral part of the Marvel Universe, it could be a liability on film. In contrast, Lang's Ant-Man had a compelling history as a good-hearted thief and family man. In Peyton Reed's Ant-Man, that digestible story gave audiences a perfect introduction to Paul Rudd's Scott Lang. Although Pym still has a role as one of the MCU's many scientific geniuses, Lang gave the MCU some much-needed low-key charm.

11 PEPPER POTTS

Pepper Potts Gwenyth Paltrow

After her introduction in 1963's Tales of Suspense #45, by Stan Lee, Robert Bernstein and Don Heck, Pepper Potts was a regular in Iron Man's supporting cast in the 1960s. In addition to being Tony Stark's secretary, she was part of the title's central love triangle between Tony and his driver Happy Hogan. When she married Hogan, the pair mostly left Iron Man's until the late 1990s. After rejoining Stark Enterprises, Happy died, and Potts took on an increasingly important role in Stark's business affairs.

In the MCU, Gwyneth Paltrow's Pepper Potts has a more or less streamlined version of her comic book history with a few major alternations. Instead of marrying Hogan, Pepper's relationship with Stark is at the emotional core of Iron Man's solo cinematic outings. This culminated with her temporarily gaining super-powers and killing Aldrich Killian, the main villain of Iron Man 3.

10 KAECILIUS

Mads Mikkelson as Kaecilius In Dr Strange

While Scott Dickerson's Doctor Strange featured the Sorcerer Supreme's famous mystical foes Dormammu and Baron Mordo, the 2016 film gave most of its screen time to a far more obscure villain, Kaecilius. Created by Stan Lee and Steve Ditko in 1965's Strange Tales #130, the evil sorcerer didn't even make a dozen appearances before his cinematic debut.

While he was Baron Mordo's long-forgotten apprentice and sidekick in the comics, Mads Mikkelsen's Kaecilius served a different master in the MCU. As a disciple of the dreaded Dormammu, he was a far more imposing threat than his sniveling comic counterpart. While Strange ultimately foiled his plans, Kaecilius was still responsible for the deaths of Daniel Drumm and the Ancient One, two of the MCU's most powerful Masters of the Mystic Arts.

9 NEBULA

Nebula Karen Gillan

Like many of Marvel's cosmic characters, Nebula's most noteworthy comic moments came during Jim Starlin, Ron Lim and George Perez's iconic 1991 crossover  Infinity Gauntlet. Shortly after she was created by Roger Stern and John Buscema in 1985's Avengers #257, the space pirate claimed that she was the granddaughter of Thanos. After being tortured by Thanos, she briefly held the all-powerful Infinity Gauntlet before fading into the obscurity of Marvel's forgotten cosmos.

In the MCU, Karen Gillan's Nebula has taken on a more visible, central role. In Guardians of the Galaxy, she was Thanos' daughter and one of his chief lieutenants. James Gunn's follow-up, 2017's Guardians of the Galaxy Vol. 2, highlighted Nebula's relationship with her sister Gamora and their shared animosity towards Thanos. While her comic book counterpart has kept up her villainous ways, the MCU's Nebula became an uneasy ally to Marvel's cosmic heroes in the MCU.

8 OBADIAH STANE

Obadiah Stane Jeff Bridges

Like many of Tony Stark's comic book foes, Obadiah Stane, the Iron Monger, is essentially an evil version of Iron Man. Created by Dennis O'Neil and Luke McDonnell in 1982's Iron Man #182, Stane was an evil businessman who wanted to take over Stark Industries. While he took over Stark's business and built an armor suit of his own, Iron Man eventually defeated the Iron Monger, who killed himself in disgrace.

In Jon Favreau's Iron Man, one key twist distinguishes Jeff Bridges' Stane from his comic counterpart. In that 2008 movie, Stane helped lead Stark Industries and worked closely with Tony. When the depth of his involvement in the attack that crippled Stark was revealed, Stane's once-in-a-lifetime betrayal became a big part of Iron Man's cinematic origin. Since Iron Man was Marvel Studios' first movie, Stane also has the distinction of being the first supervillain audiences saw in the MCU.

7 YONDU

Yondu Michael Rooker

Other than his appearance and a whistle-controlled arrow, the original Yondu doesn't have much in common with his cinematic counterpart. Created by Arnold Drake and Gene Colan in 1969's Marvel Super-Heroes #18, Yondu was a member of the original Guardians of the Galaxy, who lived in the distant future of an alternate reality. While his blue skin and fin gave him a memorable look, Yondu went close to a decade between appearances before those Guardians starred in a long-running 1990s series.

In 2014's Guardians of the Galaxy, Michael Rooker's Yondu was a loud-mouthed, disreputable space pirate who raised Star-Lord. While he had an antagonistic role in that movie, Yondu became a far more sympathetic character in the sequel, especially with regards to his role as Star-Lord's surrogate father. After his MCU debut, an identical version of that Yondu was introduced to Marvel's comics in 2016.

6 YELLOWJACKET (DARREN CROSS)

Yellow Jacket Darren Cross Corey Stoll

In the MCU, the evil businessman Darren Cross became the size-changing Yellowjacket in 2015's Ant-Man. While that might seem fairly straightforward, it brought together two distinct parts of the tiny Avenger's history. Traditionally, Yellowjacket was an identity that Hank Pym used during his most unstable period. The other half of that equation, Darren Cross, was an obscure character who had only appeared in two comics before his cinematic debut.

Created by David Michelinie and John Byrne in 1979's Marvel Premiere #47, Cross was a millionaire with an experimental pacemaker that burned out his heart in his second appearance. In Ant-Man, Corey Stoll's Cross brought these two concepts together to create a new villain that made good use of Ant-Man's history. Around the film's release date, Cross came back to life and donned a forgotten suit of armor to become Yellowjacket in comics too.

5 J.A.R.V.I.S./VISION

JARVIS Vision Paul Beattany

Over the years, Iron Man has used a few different artificial intelligence systems in his armor. In the early 1990s, H.O.M.E.R. helped guide Tony Stark in comics and in Iron Man's animated series. Another A.I. turned evil and took over Iron Man's suit in a well-regarded 2000 storyline by Joe Quesada and Sean Chen. Still, Stark's subsequent A.I. efforts like Friday and H.E.L.E.N. were mostly helpful, if unremarkable, assistants.

In 2008's Iron Man, Paul Bettany gave his voice to J.A.R.V.I.S., Tony Stark's cinematic armor A.I. After appearing in several films, this A.I. formed the basis for the Vision's programming in 2015's Avengers: Age of Ultron. While Iron Man's comics A.I.s never made a lasting impression, J.A.R.V.I.S. evolved into one of the Avengers' most iconic members. Since he has an Infinity Stone, Bettany's android Avenger seems set to play a central role in 2018's Avengers: Infinity War.

4 ALEXANDER PIERCE

Alexander Pierce Robert Redford

Like several of the other characters on this list, Alexander Pierce rose from the depths of obscurity to become the primary villain in one of the MCU's films. Created by Bob Harris and Paul Neary in 1988's Nick Fury vs. S.H.I.E.L.D. #3, Pierce was a S.H.I.E.L.D. agent who served as Nick Fury's right-hand man throughout the early 1990s. Pierce resurfaced in 2010 as the leader of Team Black, one of Fury's most trusted squads.

In the Russo Brothers' 2014 film, Captain America: The Winter Solider, Robert Redford's Pierce played a very different role. Although he seemed to be Fury's friend and a benevolent government bureaucrat, Pierce was secretly a Hydra double-agent who helped spearhead their infiltration within S.H.I.E.L.D. While Pierce could've been used in a number of ways on Agents of S.H.I.E.L.D., this key cinematic part gave Pierce a memorable role with a distinctive impact on the larger MCU.

3 ALDRICH KILLIAN

Aldrich Killian Guy Pearce

Although Shane Black's Iron Man 3 was partially sold on the promise of Ben Kingsley's take on the Mandarin, Guy Pearce's Aldrich Killian was the film's true villain. In the 2013 movie, Killian was a scientist who founded A.I.M. and developed the Extremis virus, which gave him heat-based and regenerative powers. In the film's explosion-filled climax, he used those abilities to tear through Tony Stark's army of Iron Man suits, revealed a giant, previously unseen dragon tattoo and said that he was the real Mandarin.

While that twist caused some minor controversy among fans, Pearce's villain is a far cry from his comic book counterpart. In the Marvel Universe, Dr. Aldrich Killian's first and only appearance came in 2005's Iron Man #1, by Warren Ellis and Adi Granov. While he was still one of Extremis' creators, he sold a sample of the virus to some criminals before unceremoniously killing himself.

2 HOPE PYM/HOPE VAN DYNE

Wasp Evangeline Lily

While Evangeline Lily's Hope Van Dyne will have a starring role in 2018's Ant-Man And The Wasp, her comic counterpart didn't even debut in the Marvel Universe. In the late 1990s, Marvel published MC2, an imprint of alternate reality titles that starred the next generation of superheroes. In 1999's A-Next #7, by Tom DeFalco and Ron Frenz, Hope Pym debuted as a villain who battled that timeline's Avengers. She was the daughter of that world's Hank Pym and Janet Van Dyne, and she formed the Revengers with her brother, Hank Jr., to keep the new Avengers from disrespecting their parents' memory.

In the MCU, Lily's Hope van Dyne is a more heroic character. While she had some unresolved issues with her parents, she still helped hank Pym train the second Ant-Man, Scott Lang, and embraced her mother's legacy as the Wasp by the film's end.

1 BLACK WIDOW

Black Widow Scarlett Johanssen

Since she was created by Stan Lee and Don Heck in 1964s' Tales of Suspense #52, Black Widow has done a lot. Even though she led the Avengers, Natasha Romanoff was more famous for her long partnership with Daredevil and her involvement in the espionage-filled world of S.H.I.E.L.D. While she occasionally starred in her own miniseries, Black Widow bounced around titles and could go the better part of a year without appearing.

In the MCU, Scarlett Johansson's Black Widow changed that. After debuting in 2010's Iron Man 2, Romanoff rocketed to Marvel's A-list thanks to her significant role in 2012's The Avengers. Thanks to that movie's blockbuster success, Black Widow has gone from occasional supporting character to Marvel's most recognizable heroine. In an unfortunate reflection of her comic roots, Johansson's Widow still hasn't had a movie of her own, despite the character's worldwide fame and popularity.

Keep it locked to CBR for all the latest news on the Marvel Cinematic Universe, and let us know who your favorite former C-lister is in the comments!