Ian Somerhalder, Cassidy Freeman Ian Somerhalder, Cassidy Freeman

Smallville fans: Meet the vampire version of Tess Mercer.

Cassidy Freeman, who portrayed the fearless illegitimate daughter of Lionel Luthor on the CW superhero drama, will make her first appearance on Thursday's episode of The Vampire Diaries, in which she plays a ruthless and seductive vampire who was something of a mentor to a younger Damon (Ian Somerhalder). Before the "Delena" fans start to worry, know this: Sage has her eye on another vampire who's a bit more powerful. TVGuide.com caught up with Freeman to get the scoop on her Diaries debut.

The Vampire Diaries Bite: Learn why Sage and Rebekah have a tense history

What kind of person is Sage?
Cassidy Freeman:
Sage has been a vampire for a very long time, so she has the ability to suss out what the best parts of being a vampire are. She's a live-in-the-moment and live-life-to-the-fullest kind of woman, so she's enjoying being a vampire as much as one can enjoy being undead. She's willing to take people like Damon under her wing and teach them the ways of being a pretty badass vampire. She's like a snake, so she definitely has a seductive way about her.

How is she different from Tess Mercer?
Other than being hundreds and hundreds and hundreds of years old? [Laughs] They actually have a lot of similarities in that they're both strong women. They both have a really genuine core to them and they are always out for their own motives, which is really interesting. Sage is definitely looser than Tess. She's more [of a] take-your-hat-off, undo-the-tie, take-your-shoes-off kind of girl. She's much more willing to be free than Tess was. Tess was very buttoned-up, very professional, and hid her emotions.

How does Sage change Damon in both the past and the present?
In the past, she affects him a lot. He [was] pretty unsure of himself as a vampire, and doing things maybe not as gracefully as he could. Her role in the past is really to show Damon the way of being the vampire that maybe he was always destined to be. She's definitely a mentor to him. In the present, they're more like peers because he's lived the life he's lived over the last however many years and she's come back to suss things out in the present day and see if she can get what she wants.

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Is there a possibility for them to hook up?
They definitely have sexual tension. There's not some long-lost burning love between them. Damon has sexual tension with everything! [Laughs] I also think that Sage is a similar character. By no means is she celibate, but at the same time, her focus is Finn (Caspar Zafer).

Will she try to rekindle things with Finn?
When someone is your true love from long ago, you always want to see if that's still there. I don't think she necessarily has that kind of patience, but she definitely has hope. She comes back in present day primarily to look for him.

How will Rebekah (Claire Holt) feel about Sage coming to town?
They didn't get along in the past and they are snippy with each other. When you want something, you will go to whoever will help you. They're definitely doing the whole circling each other routine. They do end up interacting in the present in maybe more than one way.

How does Sage interact with the rest of the Originals?
Kind of like your first high school boyfriend or girlfriend does with your family. They all know who she is, and they didn't think very highly of her back in the day. They think very highly of themselves, and they don't think Sage is as high as they are.

Watch this week's Vampire Diaries Bite for more from Freeman and Holt:

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