Who is he: William Stryker
His power: None, although his obsessive hatred of mutants is extraordinary.
His story: William Stryker Jr. is a military man who really, really hates mutants. After Magneto and Mystique, he’s the villain that appears most often in the XMU, and unlike those two mutants, Stryker is never portrayed as an antihero. He’s a piece of shit through and through, starting with his first film appearance in X2, where he drugs mutants into doing his bidding, attacks Xavier’s School For Gifted Youngsters, and tries to use Charles Xavier’s telepathic abilities to kill all mutants on the planet. Maj. Stryker plans to accomplish that by using the psychic illusions created by his mutant son, Jason, who is also the source of the mind-control drug because Stryker is the worst dad ever. The combined forces of the X-Men, Magneto, and Mystique stop Stryker’s plot, and Magneto chains the villain to a concrete block where he dies in the rush of water from the broken Alkali Lake dam.
Various films after X2 have explored Stryker’s relationship with mutantkind in the past. In the original XMU timeline, Stryker worked with Bolivar Trask to capture mutants that were experimented on during the early stages of the Sentinel program, as shown in the first two acts of X-Men: Days Of Future Past. After Mystique assassinates Trask, Stryker creates his mutant strike force, Team X, and continues to experiment on mutants with the Weapon X and Weapon XI programs (X-Men Origins: Wolverine). In the altered timeline after X-Men: Days Of Future Past, Stryker reappears to kidnap some mutants again in X-Men: Apocalypse, and it’s revealed that the Weapon X program is still active in the new continuity and still responsible for giving Wolverine his adamantium skeleton. The young X-Men released Wolverine from his cage, but Stryker still manages to escape, free to return whenever mutants need capturing.
Played by: Josh Helman in X-Men: Days Of Future Past and X-Men: Apocalypse, Danny Huston in X-Men Origins: Wolverine, and Brian Cox in X2
Currently, William Stryker is: Plotting how he can make those meddling mutants pay the next time.
Where will we see him next? There are no plans for William Stryker to show up in the future, but the guy gets around, so he could appear in any number of upcoming projects, from the next X-sequel to Deadpool 2. (He skipped out on Logan, though.)