The animated X-Men of the 1990s are returning to the small screen in Marvel's X-Men '97 on Disney+. The series is set to debut later this year, continuing the story of 1992's X-Men: The Animated Series. Recently revealed plot details hint at the series' new status quo, with Magneto stepping into Charles Xavier's old role as leader of the X-Men, while the team's remaining members try to keep the X-Men up and running in Professor X's absence. However, while Magneto may be set to join forces with his old adversaries, another enemy of the team is about to return and continue causing trouble.
Mister Sinister plagued the X-Men throughout the animated series' original run. Originally a geneticist named Nathaniel Essex, in the comics this villain was transformed into his ageless superpowered form by the ancient mutant Apocalypse. In the animated series, it was Essex's own experimentation that transformed him into Mister Sinister. Following a voice cameo at the very end of X-Men Season 1, Mister Sinister would go on to make his full debut as the main villain of Season 2, depriving Professor X and Magneto of their powers in the Savage Land. Sinister would continue to appear until the series' fifth and final season, which left the door open to his return in the upcoming revival.
Mister Sinister's Final Appearances in X-Men: The Animated Series
There are two episodes of X-Men: The Animated Series' fifth season that can lay claim to featuring Mister Sinister's final appearance. The last time the character was actually seen X-Men was in its penultimate episode, "Descent." However, this episode took place in the past, revealing how the Victorian-era geneticist Nathaniel Essex became Mister Sinister. The episode also revealed a friendship-turned-enmity between Sinister and Charles Xavier's ancestor, Dr. James Xavier. Essex was shown to have become obsessed with Charles Darwin's theory of evolution, driving him to conduct the experiments into mutation that would result in his own physical transformation.
While "Descent" was the last episode of X-Men to feature Mister Sinister, chronologically his final appearance occurred in "The Phalanx Covenant: Part II." This episode saw the X-Men pitted against the Phalanx, a cybernetic alien life form that sought to assimilate the population of Earth. This shared threat saw an unlikely alliance formed between Mister Sinister, Magneto and the X-Men. At the episode's end, when the allied mutants were gathered and the Phalanx defeated, Cyclops asked where Sinister had gone. The villain was then seen making a rather underwhelming escape, running into an alley in the background. Cyclops went to give chase, but Jean Grey told him to let Sinister go, so they could return home after their grueling battle with the Phalanx.
Mister Sinister Returns in X-Men '97
X-Men '97's latest synopsis reveals Sinister's role as the series' chief antagonist. It is a direction that makes sense, with Sinister still on the loose as of the end of the original series and Magneto now joining the ranks of the X-Men. Sinister looks set to fill the role formerly held by Magneto as the X-Men's principal enemy, representing a different brand of threat -- whereas Magneto was fighting for mutant supremacy over humans, Mister Sinister is not a mutant himself and seeks to exploit mutants' abilities to reshape the world as he sees fit. Given his various defeats at the hands of the X-Men in the past, he also has a personal vendetta to exact upon the mutant heroes.
Other returning villains in X-Men '97 include the Hellfire Club and the militant anti-mutant organization, the Friends of Humanity. Doors are certainly open to other old foes returning as well. Apocalypse -- who originally met his doom in Season 4 -- was resurrected in Season 5. "The Fifth Horseman" saw Apocalypse possess the body of one of his acolytes, but his story was never continued beyond this point. The Season 4 finale also teased the arrival of Immortus, an identity of Kang the Conqueror, though this was also left unexplored. Whatever threats may return to terrorize the X-Men though, Mister Sinister is set to be their first great obstacle in the animated revival. Cyclops may come to regret not chasing him down that alley.