The Vampire Diaries may be in its final season, but it's not slowing down on the surprises any time soon. The most recent episode ("An Eternity of Misery") revealed that Alaric and Caroline's "hot nanny" Seline (Kristen Gutoskie) was actually the second siren — a.k.a. the cannibalistic servant of Satan, or, in this case, Cade.

However, just because the last time we saw Seline she was chewing on poor Georgie's tendons doesn't mean that she's completely evil. (She's cunning and calculating, yes, but she does genuinely have feelings for Alaric.) After all, The Vampire Diaries has never given us a completely irredeemable villain.

"As much as she can be deliciously bad, she also does have this deep, fragile humanity," Gutoskie told MTV News ahead of Friday night's (November 18) all-new episode. That humanity will be tested when it comes to Alaric and Caroline's twins, as Seline's intentions for the girls are far darker than we anticipated. Does Seline plan to break her and her sister Sybil's agreement with Cade by turning Lizzie and Josie into the new sirens?

"They're two sisters with these incredibly immense powers, and Seline sees them as younger versions of her and Sybil," she said. "She becomes very interested in the twins for that reason, and it takes a dark turn."

Tensions between Caroline and Seline have been subtly escalating since Alaric hired the seemingly innocent nanny, so this will not bode well for Seline's future employment opportunities. As for a potential showdown between the two? It's only a matter of time before Caroline "gives Seline a piece of her mind."

"Caroline wasn't happy with the nanny in the first place, so I don't think Seline can really do much to get in Caroline's good graces," Gutoski added. "If you don't like how I'm cutting their carrots or making their cookies, you're not going to like when you find out that I'm evil. Shit's going to hit the fan."

But at least Seline will always have her sister, and fellow siren, Sybil to count on for support — oh, wait. As it stands, Seline and Sybil are currently in a fight. Sybil's upset at Seline for leaving her behind in The Armory, and for her part, Seline used Georgie to get back on her maniacal sister's good side. There's so much resentment and strain between these two, you'd think we were talking Damon and Stefan.

"Sybil and Damon are very similar," she said. "They were both made immortal and forced into this violent existence by their siblings. What's similar in Stefan and Seline is that they seem to have these two completely different sides to them — Stefan can be very compassionate and loving and caring, and then he can go into Ripper mode and be this sociopathic killer. Seline has similar dualities in her, and like Stefan, they both do things with the intention to maybe help but it ends up hurting people more. She wanted to save Sybil, but in the end, it actually ended up hurting her."

And then there's Cade, the devilish puppet master pulling Seline and Sybil's strings. At the end of the day, they answer to him — which makes Cade a fearsome Big Bad for the show's final season. According to Gutoski, however, you shouldn't be too quick to judge Cade; he may be Satan, but even the devil had to start somewhere.

"They've had to do a lot of bad things in his name for thousands of years, but you also see that he started out as a really good human who was made an outcast for being different," she said. "What you're seeing from him and the sirens — and what you see through all of The Vampire Diaries — are these characters who act out because they were [cast out] for being different. As bad as Cade is, hopefully there's something redeeming in him too."

Of course this show would make us sympathize with the Devil.