The Leader: In the comics, the Hulk’s arch-enemy is brainy bad-guy Samuel Sterns, AKA the Leader. Sterns was introduced into the MCU in The Incredible Hulk (2008), played by Tim Blake Nelson. In the film, Bruce Banner (Edward Norton) seeks help from oddball scientist Sterns, who proves to have his own agenda. He has synthesized samples of Banner’s irradiated blood, hoping to tap into its “limitless potential”. When last we see Sterns, he gets some of the Banner-Blood into a wound on his forehead. He smiles as his head starts to grow.
And that’s it. We never see him or hear about him ever again. We know that he was being set-up for The Incredible Hulk 2, which never got made. Still, there’s no reason he couldn’t be utilized in some capacity. There was some speculation that he was secretly the Clairvoyant in Agents of SHIELD but that turned out to be false. We know the Leader is out there somewhere, so it would be fun if Marvel decided to utilize one of its best super-villains, especially since he’s already been given an on-screen origin.
The Mandarin: Every comic fans was cursing with disgust after the ridiculous revelation about the fake Mandarin AKA Trevor Slattery (Ben Kingsley) in Iron Man 3. However, Marvel decided to make it up to the fans in the 2014 short film All Hail the King (which was released as part of the Thor: the Dark World DVD/Blu-ray release), which continues Slattery’s story as he arrives in prison. Slattery finds out that his impersonation of the Mandarin has infuriated the 10 Rings terrorist group and their commander—the real Mandarin! When Slattery was hired to act as the Mandarin, he didn’t realize that he was being asked to impersonate an actual criminal. At the end of the film, Slattery is kidnapped by the 10 Rings to be brought for judgment in front of the real Mandarin. (Who we never see.)
Since then, we’ve never discovered what happened to Slattery and, more importantly, we’ve never seen the real Mandarin. We know he’s out there in the MCU somewhere, running the 10 Rings, but he seems to be keeping a very low profile. Obviously, Marvel had no long-term plans for the character and the only reason we got a real Mandarin is because of the hostile fan reaction to the plot-twist in Iron Man 3. The Mandarin is one of Marvel’s best villains and he could be an interesting addition to the MCU, considering they seem to be having trouble creating good villains.
Graviton: One of the most powerful supervillains in Marvel Comics, Dr. Franklin Hall AKA Graviton, has already been introduced to the MCU on Agents of SHIELD. In the first season episode “The Asset”, we meet Dr. Hall, a scientist who goes rogue in a misguided attempt to stop SHIELD from mastering the power of the element ‘gravitonium’, which can alter and control gravity. At the end of the episode, Hall is sucked into a big blob of gravitonium. After the blob is secured in a chamber, a final shot of it shows a hand reaching out. Obviously, this was Hall, so we can assume that he has become Graviton and escaped the big blob. So where has he been since then? How does a being with such incredible power fly under the radar for so long? Graviton would make a formidable foe for the Avengers in a future film.
The Abomination: The man-monster with the strength of the Hulk was introduced into the MCU in the Incredible Hulk (2008). Born Emil Blonsky, (Tim Roth) he was a commando who was given both the super-soldier formula and a sample of Bruce Banner’s blood, being mutated into the powerful Abomination. After going berserk in NY and finally being defeated by the Hulk, the Abomination is captured. We learn in an episode of Agents of SHIELD that Blonsky is being held in a cryo-cell in Barrow, Alaska. When the World Security Council was compiling the initial membership for the “Avengers Initiative”, they planned to release Blonsky, pointing out that he was once a war hero and that he only wreaked havoc because he was trying to defend himself from Hulk. They intended to make him a member of the Avengers, but S.H.I.E.L.D., Tony Stark and General Ross would not sanction it. Therefore, as far as we know, the Abomination is still a prisoner in Alaska. He could easily be used in a future film, even if he’s not the main villain. He could be a lackey for Thanos or some other major MCU bad guy.
Do you think we’ll ever see these Marvel menaces again? Do you want them to appear? Did I miss any ‘forgotten’ MCU villains?