I’ve written before about my love of well-drawn villains, by which I mean villains with understandable motivation and rational characteristics. I’m not partial to “motiveless malignancy”, which is why I’m not interested in psychopathic serial killers. But give me somebody who has a reason for doing what he or she does, even if that reason is despicable, and I’m frequently fascinated. You know the kind of person I’m thinking of, right? Somebody like Mary Balogh’s villain in Slightly Scandalous, a rather horrible woman who feels perfectly justified in her actions. Or the awful mayor in Linda Howard’s Open Season, who’s annoyed with people who just don’t understand his plans. Or Mags Bennett in Justified.

Of course, most people met Mags over a year ago—Margo Martindale, the actress who plays Mags, won an Emmy for her work. But I watch Justified on DVD, and I’m just now making her acquaintance. Let me tell you, Mags is one scary woman.

Which is not to say she’s Cruella Deville. Thanks to the Justified production designer, Mags looks and sounds like just another country woman. She favors faded housedresses and flannel shirts along with oxfords and crew socks. She’s somewhat dumpy and heavy-bodied herself, with her nondescript brown hair pulled back in the sort of ponytail that leaves chunks hanging around her weathered face. And her voice is a smooth, even-toned drawl.

Everybody in the area knows Mags and her two sons grow marijuana (actually all three sons, but one son is nominally a cop). What they don’t know, at the beginning of the season, is that Mags and her sons are planning to manipulate their way into getting a lot of money from a coal company, and that Mags has no compunction about killing anybody who gets in her way. She sends her son and another minion to torture a man whose fourteen-year-old daughter, Loretta, harvested marijuana on state land she considers hers. And when she discovers that said trafficker reported one of her men for trying to molest his daughter, she decides to kill him.

But this is where it gets interesting. Because Loretta has also come to Mags for help, and Mags has promised that said molester will be punished. When she poisons the father (placing the poison in his glass rather than the bottle so that she and her son can drink with him safely), she assures him that she’ll take care of Loretta and tells him, as he’s dying, that he’s going to be reunited with his beloved wife. And then she tells Loretta (who thinks her father has been sent out of state by Mags) that she’s looking forward to taking care of her because she’s only had boys to raise before.

All of this is, as I say, scary as hell—at least in part because Margo Martindale is so good. You believe Mags. Both when she’s being maternal and when she’s being murderous. When she tells the dying man, “I’ll raise her as my own,” it’s not only believable, it’s appalling—a much worse threat than physical violence.

Of course, Mags comes to no good end. The name of the show is Justified, after all, and the hero, Ryland Givens, is suitably relentless in his pursuit of the bad guys. Plus he’s suitably concerned about the fate of Loretta in Mags’s care, a concern that’s well-founded as it turns out.

But Mags’s double nature, her maternal concern for Loretta along with her total ruthlessness when it comes to her business interests, is what makes for a good villain, at least in my opinion. Sadism is both boring and icky. But someone like Mags, someone who believes she’s absolutely justified in doing what she does because of who she is—that’s terrifying. And fascinating. So let’s hear it for Margo and Mags. And for good villains everywhere.