X-Men: The Animated Series defined Marvel’s mutants for a whole generation who grew up watching them in the ’90s. That’s why the upcoming X-Men ’97 Disney+ series, which picks up where the classic show left off, has as much fan anticipation as any live-action MCU series. But aside from a few character designs shown at Comic-Con last summer, we know little about the new show—until now. A writer for the series has revealed the main villain, and he’s as classic an X-Men foe as they come. X-Men ’97’s villain for season one is none other than master manipulator Mister Sinister.

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Via The Direct, we learned that at the recent 60 Uncanny Years live virtual event, celebrating six decades of the X-Men, X-Men ’97 writer Beau DeMayo confirmed that amoral geneticist Nathaniel Essex, a.k.a. Mister Sinister, would feature prominently in the show’s first season. Christopher Britton, who voiced the character in the original series, will reprise the role. Here’s what DeMayo had to say about the returning mad scientist villain:

A very, very, very, very favorite character of mine and many others, Mr. Sinister, will rear his ugly head from the past with a pretty foolproof plan to destroy the X-Men once and for all.”

Mister Sinister has been a thorn in the side of the X-Men in the comics since 1987. We learned in the comics that he manipulated the gene pool of the Summers family for generations, particularly Scott Summers (Cyclops) and his brother Alex (Havok). Sinister cloned Jean Grey after her apparent death, creating the doppelgänger Madelyne Pryor. He arranged for her to meet Scott and marry him, producing a powerful son. A son who would grow up to become the mutant mercenary called Cable.

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Much of Mister Sinister’s comics backstory made it into the classic cartoon. In more modern comics, Sinister has been an uneasy ally of the X-Men, but has just as often betrayed them. Unlike Magneto, he’s just one of those villains who can’t ever seem to turn over a new leaf. As the new series will feature Magneto in charge of the X-Men, taking over from Xavier, we can’t wait to see a Sinister vs. Magneto showdown for the ages.

X-Men ’97 will release on Disney+ sometime this fall.