Fear the Walking Dead's third season won't just have zombies to contend with, because a demon is headed to the series. Well, a demon in a past life, anyway.

AMC's The Walking Dead spin-off has cast Emma Caulfield in a secret role, TVLine reports. Caufield will join the series as a guest star, but it's currently unknown who she will play, how many episodes she'll be around for or any other details. All we know is she'll be there.

You'll remember Caulfield as Buffy the Vampire Slayer's Anya Jenkins, a vengeance demon who struggled with understanding the human condition once she was turned mortal. Caulfield also starred as Susan Keats on Beverly Hills, 90210 and played the Blind Witch in Once Upon a Time.

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Who do you think she'll play in Fear the Walking Dead?

Fear the Walking Dead will return sometime this year on AMC.