Negan, eat your heart out.

The Walking Dead has cast its new big-bad for season nine: Samantha Morton, who joins the cast in a series-regular role as Alpha, leader of the Whisperers, one of the most iconic villains from the comic books on which the AMC drama is based. Executive producer and Walking Dead comic book creator Robert Kirkman announced the news Friday at San Diego Comic-Con.

Morton's casting ends months of speculation on a couple different fronts, both about who would end up playing the aggressive Alpha and also whether or not the Whisperers as an obstacle would wind up in season nine. Their inclusion already felt like a foregone conclusion, given the Walking Dead TV series' current place in the process of adapting Kirkman and Charlie Adlard's comic book series. Now with Morton's casting, not to mention a stinger at the end of the Comic-Con trailer, the Whisperers' arrival is confirmed.

For Walking Dead fans unfamiliar with the comic books on which the AMC drama is based, the Whisperers are the next and thus far most eclectic group of adversaries pitted against Rick Grimes (Andrew Lincoln) and his allies. In the comics, the Whisperers survive in the wild by wearing skin suits made of human flesh, designed to allow them to blend in with the walkers. What's more, they believe that the zombie apocalypse is the rightful next step in the evolution of society, a restoration to the natural order of things.

As Alpha, the Oscar-nominated Morton (Sweet and Lowdown and In America) will embody the leader of the Whisperers, a ruthless woman who is bald beneath her zombie mask, charged with presiding over the rest of her people. In the comics, she's close with two specific members of the clan: Beta, her enormous lieutenant, and Lydia, her daughter, who becomes a love interest for Carl. Given Chandler Riggs' exit from the series in season eight, any and all future storylines involving Lydia will clearly need to undergo some alterations.

Outside of her relationships within the Whisperers, Alpha's interactions with characters outside her group are notable. She's very quickly at odds with Rick Grimes, with the two leaders fully opposed to each other's way of life. Indeed, Alpha makes the full extent of her threat level known in a grand gesture to Rick that involves the deaths of several members of his society, including two characters who are still active in the AMC series. No spoilers on those specific casualties, though given news of Lincoln's exit, one wonders if Rick himself will wind up on the receiving end of Alpha's wrath.

Beyond Rick, Alpha has a few memorable interactions with another leader in the zombie apocalypse — but to say much more on that front would be getting way too far ahead of the game. Alpha represents the biggest villain to enter the Walking Dead fray since the series cast Jeffrey Dean Morgan as its first big-bad, Negan.

For her part, Morton counts Hulu's Harlots, Fantastic Beasts and Where to Find Them, Minority Report, The Messenger and Her among her impressive lists of credits. She is repped by UTA and the U.K.'s Conway van Gelder Grant.

Morton is among a laundry list of new faces joining The Walking Dead in season nine as the AMC series launches its creative reset following a major time jump. Others joining the series in recurring roles are Brett Butler (as Tammy), John Finn (as Earl), Rhys Coiro (Jed), Dan Fogler (Luke), Zach McGowen (Justin) and Angel Theory (Kelly). All are expected to recur in season nine, which will explore the rebuilding of civilization post Negan and Rick's All-Out War.

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