Sybil (Nathalie Kelley) is the most ruthless villain The Vampire Diaries has had in some time, but that doesn't mean there isn't a heart in there somewhere - or at least there used to be.

As Kelley tells TVGuide.com, Sybil was once just a regular human who was later turned into a siren alongside her sister. And even before gaining these supernatural abilities and murderous agenda, Sybil and her sister's lives were filled with tragedy and strife - not unlike Stefan (Paul Wesley) and Damon's (Ian Somerhalder) own tumultuous history.

To find out what else Kelley revealed about Sybil's origin story - and what her master plan is now - check out the full interview below.

TVGuide.com: They've now got Sybil trapped in the Armory. How does she respond to being held captive again?
Nathalie Kelley:
I think there's nothing she hasn't experienced. She's so old. She's done so many things before so many times. She knows she'll get out. This isn't particularly devastating for her. She's a very powerful, very old immortal. She's ticked off and annoyed, but she's not super worried about her fate.

Even if she can't use her mind control powers now, how might we see Sybil try to manipulate everyone around her?
Kelley:
That's how she operates. She only has one mode of operation and that's manipulation. Actually, in this episode she reveals quite a bit about herself. She reveals how she became a siren, you find out about her backstory. Her and Stefan have a really long chat and in this reveal. She's really also trying to reveal something about Stefan to himself. In a way, the reveal is like a manipulation. She wouldn't be telling him her backstory if it didn't serve her.

We learn Sybil has a sister this week. What can you tell us about her?
Kelley:
They share a story about how they become sirens and that's what you will learn in the next episode. They're very, very old and there's a lot of tragedy about how they came to this island and eventually turned into sirens.

Will we see a lot of parallels between Sybil's relationship with her sister and Stefan's relationship with Damon?
Kelley: A lot, actually, and that's part of the reason she reveals so much to Stefan, because there's a lot of mirroring in these sibling relationships. She actually asks some really deep questions of Stefan this episode, and those scenes were really fun to play with Paul. There's a lot of digging up old stuff and facing yourself and looking in the mirror this episode.

The Vampire Diaries: Will Damon become human to be with Elena?

How has your perception of Sybil changed the more you've learned about her?
Kelley:
No one wakes up and just becomes evil overnight, and so the more I learn about her backstory, the more I fell in love with her as a character. She was human at a point and she had a lot of tragedy happen to her. I'm learning about her too with every new episode I get.

What would you say are Sybil's main motivations?
Kelley: Well, there's definitely a desire to be loved, which is what attracted me to the character in the first place — how somebody could simultaneously be so lacking in compassion and empathy and so evil, and at the same time so desperate and needy for love. Bonnie (Kat Graham) said something interesting in the last episode, which is that one of the reasons she doesn't like Bonnie is that she has friends and people who love her by choice, and that's something Sybil's never had. She's had to siren any of her relationships. She doesn't have friends. She has people she mind-controls.

You find out there was a lot of abandonment she experienced as a child, so I think that's what really drives her — to mask those old wounds. And she masks them by sirening people to do her bidding, and she's sirening Damon and Enzo (Michael Malarkey) partially for the company too. She had this tragic past and then she was in this prison for 100 years in the Armory, so she's desperate for love and companionship at this point. She's really yearning for it.

Sybil has mentally inserted herself into all of Damon's intimate memories with Elena (Nina Dobrev) and Bonnie. Is that her way of getting to play out these idealized friendships and romances?
Kelley:
Exactly. That's part of her weaving this twisted, deluded illusion. That's how she operates.

Does she have any real affection for Damon or is he just a means to an end for her?
Kelley: I think she's incapable of any kind of genuine affection for anybody, but she likes him in the way that he's a loyal servant. She knows how valuable he is to her.

Damon goes to Texas this week on a mission for Sybil. What exactly is he looking for?
Kelley:
Sybil doesn't do anything that's not calculated. She has him on a mission to get something for her that's going to benefit her in some way, and you'll find out what that is later on in the season. But it's all for her evil means.

Why did Damon and Enzo make people confess to doing bad things before killing them for Sybil? In her own twisted way, does Sybil think what she's doing is a form of justice?
Kelley:
I don't think Sybil is too concerned with justice. She doesn't have a moral compass in that way. But you'll find out why they have that talk about harvesting evil souls. It's something that she has to do, and you'll find out why in this episode. But it's not like she's some kind of vigilante because she wants to be. She would love to be doing other things, but you find out that this is like a job for her.

The idea of Hell looms over this season. How will that idea continue to be explored as this season goes on?
Kelley:
It's the final season so I think everybody has to look in the mirror and ask really serious questions about punishment and repercussions for one's past actions. The theme of redemption is strong. Are these people redeemable after doing awful things? Can you come back from that? Is redemption possible for these characters? It's a big theme and it's a fitting theme as [creator Julie Plec] is wrapping up this story.

The Vampire Diaries airs Fridays at 8/7c on the CW.

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