As Lost draws to a close, many fans are thrilled and confounded by the addition of new characters... while others just await answers.

This brings us to Sheila Kelley, the actress who plays Zoe. Introduced last week, Kelley told TV Guide she understands viewers might be frustrated by the sudden appearance of yet another new person on the ABC island, but she says her character is vital to the overall mythology.

"Just when I think she's evil, she's not. And just when I think she's not, she is," Kelley said. "The whole show right now is so much about the epic mystical story of good versus bad, and it just swings by a thread. She really believes what she is doing is the right thing to do and you'll understand that more when you see the upcoming episodes."

A couple more excerpts from the actress' interview:

On her character's name: The first thing I did was looked up the name Zoe, and it means "life" in Greek. It's a very strong mythological name and there's a lot of mythology on the island. So yes, she does.

On her profession: She is a geophysicist. I think that she's very brilliant and loves what she does. She is a maverick in her field and believes there are more answers than the status quo is willing to buy into. So she wants to bring the concrete world of physics and geology into much more esoteric happenings, like time travel and the energy of the island. She's bridging the gap between science and belief. It's a strong theme throughout the whole show.

What else? This is her first time, but she's a strategist and very cunning. She prepared very rigorously to come to the island for what she needs to do, and what she needs to do is huge. She's 20 steps ahead all the time... or she likes to believe she is.

Matt Richenthal is the Editor in Chief of TV Fanatic. Follow him on Twitter and on Google+.