By the end of 2016 there will have been 10 X-Men movies and spinoffs released theatrically and as such, many of the greatest X-Men villains of all-time have already appeared in one form or another in films, or soon will be. From Magneto, Sabretooth, and Sentinels to the Stryker, the Hellfire Club, and the upcoming introduction of Apocalypse, Twentieth Century Fox has adapted many of the top mutant menaces from Marvel Comics. But not all of them...

There are several X-Men characters who fans have been waiting many years to see explored on the big screen. We see them listed frequently in comments of X-Men articles we write about projects in development. Some we've even speculated upon ourselves, so below we've listed five such villains who Marvel readers will recognize as opponents the X-Men need to battle one day - characters who you might have mentioned yourself.

Rules: We're leaving space-based characters (i.e. Shi'ar Empire) and stories out of this list and will save that for down the road.

Mastermind

X-Men Villains - Mastermind

  • Real Name: Jason Wyngarde
  • Powers/Abilities: Memory Manipulation, Illusion Creation
  • First Appearance: X-Men #4 (March 1964)

With ties to both Magneto's Brotherhood of Evil Mutants and the Hellfire Club (seen in X-Men: First Class), Mastermind can play an interesting role in the future as the core X-Men franchise quasi-reboots itself in X-Men: Apocalypse by introducing younger versions of the original X-Men movie characters. It'd be quite fitting actually given that he's one of the first X-Men villains from the comics who later played a significant role in the Dark Phoenix Saga - a landmark story that will eventually (read: inevitably) be explored again with new Jean Grey actress Sophie Turner.

The original Mastermind in the comics (pictured above) had two daughters who carry the X-villain torch with similar codenames and powers, and play a rather significant role in several modern X-Men stories. They are even recruited into Mr. Sinister's Marauders (his team of mutant combatants) alongside X-Men hero Gambit which brings us to...

Mister Sinister

X-Men Villains - Mr Sinister

  • Real Names/Aliases: Nathaniel Essex, Nathan Milbury, Robert Windsor
  • Powers/Abilities: Superhuman intelligence, strength and durability, Healing Factor, Telepathy, Telekinesis, Shapeshifting
  • First Appearance: Uncanny X-Men #221 (Sept. 1987)

There's no X-Men character from Marvel Comics who has been mentioned in reference to a desire to see him in the movies more by fans on forums and in the comment sections of this very website than Mr. Sinister, one of the greatest villains in all of comics.

Sinister's always held an obsession for the families of Cyclops and Jean Grey and even cloned the latter, creating Madelyne Prior, whom Cyclops (who Sinister has been manipulating most of his life) had a child with. That child becomes the time-travelling mutant soldier known as Cable who's likely to be introduced in the films in the not too distance future. Sinister's team of Marauders (mostly comprised of "evil mutants") ties in with several key characters we've met in the films (Mystique, Sabretooth) and will soon meet in the future (Gambit) and can offer the X-Men heroes a very formidable opponent and Sinister himself can tie-in with a new take on The Phoenix Saga and stories involving the Summers family (Havok, Cyclops and their parents).

Omega Red

X-Men Villains - Omega Red

  • Real Name: Arkady Rossovich
  • Powers/Abilities: Superhuman physical attributes, Healing Factor, Carbonadium Tentacles
  • First Appearance: X-Men #4 (vol. 2, January 1992)

If the KGB created an evil cross between Wolverine and Captain America, that would be the best way to describe the villainous Omega Red in a pinch. A criminal in every sense of the word, Omega Red's mysterious and violent past lead him into being experimented on by Soviet Russia's version of the super soldier project. Where Wolverine's Weapon X procedure laced Logan's bones and claws with Adamantium metal, Rossovich's operation gave him retractable carbonadium (a metal similar to adamantium but flexible) tentacles in each of his arms. These not only serve as extra weaponized limbs of sorts but allow Omega Red to drain the life of victims.

With Wolverine 3 on the way and star Hugh Jackman teasing a potential return of Victor Creed a.k.a. Sabretooth, Omega Red might be the perfect villain to finally adapt to the big screen simply because of his connections to the pair. In the comics, Omega Red seeks out Victor and Logan because they may know the location of technology which may save his life.

Onslaught

X-Men Villains - Onslaught

  • Real Name: Charles Xavier
  • Powers/Abilities: Superhuman physical attributes, Telepathy, Telekinesis, Magnetism manipulation, Reality warping
  • First Appearance: X-Men vol. 2, #53 (June 1996)

Patrick Stewart teased that Wolverine 3 will feature a "very different" Charles Xavier - what if he becomes a villain of sorts? In the comics, Magneto took his villainy too in skirmish between his team and the X-Men by literally ripping out Wolverine's adamantium skeleton. This sent Xavier over the edge and he shut down Magneto's mind. But it didn't work as planned. Magneto's vengeful consciousness merged with Professor X's and created a second, villainous personality known as Onslaught which eventually took control of Xavier's mind and body.

If Twentieth Century Fox decides to bring back the Fantastic Four again after the recent reboot's failure, Onslaught's story arc in the comics allows for the Fantastic Four and X-Men to team-up.

Stryfe

X-Men Villains - Stryfe

  • Aliases: Nathan Summers, The Chaos-Bringer
  • Powers/Abilities: Superhuman physical attributes, Telepathy, Telekinesis
  • First Appearance: The New Mutants #86 (February 1990)

For years there's been talk of Cable joining the X-Men movies, and with Deadpool - his frequent partner from the comics - getting his own film next year and Cable namedropped as a must-include character for Deadpool 2 by the director, Cable could be making his way to the big screen sooner than we think. X-Men/Fantastic Four producer Simon Kinberg even teased Cable as a potential character to appear in X-Men: Apocalypse.

And where there's Cable, there's also Cable's clone Stryfe, raised in the distant future by Apocalypse. Stryfe is supremely evil and when he travels back in time to the present he creates a terrorist group, infiltrates the X-Men (posing as Cable) and uses Mr. Sinister to help spread a virus designed to kill mutants. He also wears in insanely lethal looking costume.

Josh Boone is co-writing and directing The New Mutants X-Men spinoff movie for Fox as we write this, and we'd expect Cable and Stryfe are characters who could be included.