Some of the most important supporting and side characters in the history of the Marvel Cinematic Universe have unfortunately been forgotten about and have never received the recognition they deserve. Since the MCU began with 2008’s Iron Man, dozens of notable superheroes and villains from Marvel Comics have been adapted into live-action. However, the stories of these main characters would be nothing without their supporting cast, which includes some of the most important and impactful characters in the entire MCU.
Videos by ComicBook.com
Not all of these important side characters have had the attention they deserve, and many have only been seen in one MCU movie or TV show, or even just one scene. It’s a shame that these characters have, so far, been wasted, but Marvel Studios still has the opportunity to give them more justice in the franchise’s future. It would be great to see some of these characters return to the MCU, especially if it can make more sense of their past appearances.
10) Ho Yinsen
First seen in the MCU’s debut movie, Iron Man, Ho Yinsen (Shaun Toub) had a hugely pivotal role in Tony Stark’s transformation into the titular armored hero. Yinsen was a captive of the Ten Rings faction operating out of Afghanistan who also took Stark (Robert Downey Jr.), hoping he would recreate the Jericho missile for their own purposes. It was Yinsen who saved Stark’s life by installing him with an electromagnetic and hooking it up to a car battery to keep lethal shrapnel away from his heart. Yinsen then proved essential in helping Stark build the first Iron Man suit.
The opening of 2013’s Iron Man 3 revealed that Yinsen and Stark had previously crossed paths at the Bern Technology Summit on New Year’s Eve, 1999. Yinsen had been a respected and renowned scientist who graduated from the University of Cambridge after leaving his small town of Gulmira, but fell into the hands of the Ten Rings during a rise in terrorist activity. Yinsen’s family were killed by the Ten Rings, so he was happy to sacrifice himself to set Stark free – making him one of the most important characters in the MCU’s history.
9) The Other
Despite only having a small role, the Other (Alexis Denisof) had a crucial role in introducing the Infinity Saga’s most prominent antagonist. First seen in 2012’s The Avengers, the Other was the personal servant and voice of Thanos (Josh Brolin), the Mad Titan. The Other sent Loki to subjugate Earth, readying the planet for Thanos’ arrival, though the newly-formed Avengers team thwarted their plans. 2014’s Guardians of the Galaxy then swiftly displayed Ronan the Accuser’s (Lee Pace) strength by having him kill the Other without a second thought, and, from then on, Thanos spoke for himself.
8) Nova Prime
Nova Prime Irani Rael (Glenn Close) was first seen in Guardians of the Galaxy as the commander of the Nova Corps on Xandar. Her and her forces fought alongside the Guardians of the Galaxy and the Ravagers to defeat Ronan and acquire the Power Stone, ultimately saving many lives. Despite being such an authority, Nova Prime hasn’t been seen in live-action since 2014, and now that the MCU’s Nova series has been paused, it’s unclear when she’ll be seen again. It would be fantastic for Nova Prime to return, perhaps detailing how Thanos obtained the Power Stone and “decimated Xandar.”
7) Leonard Samson
You’d be forgiven for forgetting that Leonard Samson (Ty Burrell) ever made his debut in the MCU. In Marvel Comics, Leonard Skivorski Jr. becomes the superhero known as Doc Samson after exposing himself to some of Bruce Banner’s siphoned gamma radiation, giving him superhuman strength, stamina, durability, and long, green hair. None of this was depicted back in 2008’s The Incredible Hulk, which saw Samson appear as Betty Ross’ (Liv Tyler) new romantic partner after Bruce Banner (then Edward Norton) went into hiding. Marvel recently missed the perfect opportunity to make Samson’s debut meaningful.
Captain America: Brave New World legitimized the events of The Incredible Hulk in the MCU more than any previous project. The 2025 movie marked the return of Thaddeus Ross, and included his evolution into the Red Hulk, while Betty Ross and Samuel Sterns (Tim Blake Nelson) also returned to the MCU after 17 years. The only missing piece of the puzzle was Leonard Samson, who didn’t even receive a mention in Brave New World. It would be great to see this iconic Hulk-related hero from Marvel Comics finally get justice in the MCU.
6) Dr. Helen Cho
It’s pretty surprising that Helen Cho (Claudia Kim) hasn’t made an appearance in the MCU since her debut in 2015’s Avengers: Age of Ultron. Cho is a world-renowned geneticist and friend to the Avengers, but, beyond that, she is also the mother of Amadeus Cho in Marvel Comics. Amadeus Cho goes on to become the Hulk-like superhero known as Brawn, who could be a crucial member of the MCU’s Young Avengers team. Helen Cho’s lack of development and absence for the past decade, however, leaves the futures of both uncertain.
5) Mac Gargan
The ending of 2017’s Spider-Man: Homecoming set up one of the wall-crawler’s most iconic villains from Marvel Comics making his mark on the MCU. However, Mac Gargan (Michael Mando) has not been seen since, either as himself or as the villainous Scorpion. The animated Your Friendly Neighborhood Spider-Man series showed just how great a villain the Scorpion could have been in the MCU, but the live-action Peter Parker (Tom Holland) has never had the chance to take on this legendary foe. Rumor suggests that Mac Gargan could return as the Scorpion in 2026’s upcoming Spider-Man: Brand New Day.
4) Dr. Abraham Erskine
While Ho Yinsen helped Tony Stark become Iron Man, it was Dr. Abraham Erskine who oversaw the transformation of Steve Rogers (Chris Evans) into Captain America. Erskine developed the world’s first successful super-soldier serum, and while an unrefined version was given to Johann Schmidt, turning him into the Red Skull, Rogers got the real deal. Erskine has had little mention in the years since, however, and his legacy is a series of poor attempts to recreate his work, which have soured his original design and his impact on the MCU.
3) Madame B.
The short sequence in Avengers: Age of Ultron that first introduced Madame B. (Julie Delpy) to the MCU was arguably better than the entirety of 2021’s Black Widow. Due to the Scarlet Witch’s manipulations in Age of Ultron, Natasha Romanoff (Scarlett Johansson) experienced a vision of her past when she was training to be a Black Widow assassin in the Red Room. Madame B. was her supervisor, strict and stern, who oversaw Romanoff learning to kill, and her sterilization “graduation.” If only this version of Romanoff’s history had been explored in Black Widow, rather than that including General Dreykov.
2) Aaron Davis
It’s quite baffling that Marvel Studios introduced a character so closely related to Miles Morales’ Spider-Man way back in Spider-Man: Homecoming, and hasn’t followed up on it since. Aaron Davis (Donald Glover) was seen purchasing weapons from the Vulture’s crew in Homecoming, and then later helped Peter Parker find his winged foe. Marvel fans will know that Aaron Davis is Miles Morales’ uncle in the comics, and Glover’s version of Davis even mentions his nephew, who lives in the neighborhood, yet, Miles Morales still hasn’t appeared in the MCU, eight years later.
Donald Glover recently reprised the role of Aaron Davis in the animated Spider-Man: Across the Spider-Verse movie. While the sequel is set outside the MCU’s Earth-616, produced instead by Sony Animation, Glover’s character – who sported the Prowler costume – was credited as “MCU Prowler.” This may tease Glover’s return to the MCU as Aaron Davis’ Prowler, and perhaps also teased at Miles Morales finally having a role in live-action. It would be incredible to see Homecoming’s tease paid off all these years later, and Brand New Day, Avengers: Doomsday, and Avengers: Secret Wars could make this happen.
1) Justin Hammer
In Marvel Comics, one of Iron Man’s most formidable and long-running villains is a human one: Justin Hammer. This scheming and manipulative antagonist was brought to life in 2010’s Iron Man 2 by Sam Rockwell, but, following his imprisonment, Justin Hammer hasn’t been seen in the MCU since. There have long been calls for Rockwell to reprise the role, whether that be opposite Dominique Thorne’s Riri Williams, aka Ironheart, or Don Cheadle’s Rhodey, aka War Machine. Even so, there’s still no sign of Hammer returning to the MCU, despite his appearance in the animated What If…? season 2 and the one shot “All Hail the King.”
“I’m waiting for the phone call,” suggested Sam Rockwell during an interview on The Tonight Show with Jimmy Fallon back in February 2024. “I’m growing the beard and everything. It’s been a while [since Iron Man 2]. I’m in, dude.” Rockwell has noted his openness to return to the MCU several times in the decade and a half since Iron Man 2, so it would be brilliant to see Justin Hammer finally come back – perhaps after being released from prison. Hammer could take his rightful place as one of the most important supporting characters ever.
Which supporting and side characters do you feel the MCU has wasted the most? Let us know in the comments!
Most Viewed
-
TMS Entertainment -
20th Television Animation
