Death is stalking the cast of "Lost" and people are starting to worry. It's the kind of grim reality — halfway through filming the final season of "Lost" — that can stir a devilish laugh from the show's resident bad guy, Michael Emerson.

"People have already started to become casualties, and it's only going to get worse," said Emerson, who stars as the sinister Ben Linus. "Not all the characters are going to get out of this alive."

Without question, "Lost" can be as violent as it can be mysterious. Fan favorites have gone down almost from the beginning, but with only 18 episodes left in the series, and numerous plot lines in need of resolution, "Lost" is taking what Emerson called "tragic turns."

"Everyone's question now in the cast is, 'How close to the end will I make it?' " Emerson said during a midday interview Tuesday, after winding up a day of filming.

"Every time, in the course of shooting an episode where groups break up and re-form new groups, we all try to figure out: Is that group the survivors and we're the ones who are going to be killed?"

Even he might not make it, said Emerson, who won an Emmy last year for his role.

"The writers delight in confounding the conventional expectations of their audiences," he said. "It would be just like them to kill a character that everyone thought would be the last one standing."

Either way, the 55-year-old Emerson will finish "Lost" smiling that wicked smile that made his character so much fun to hate. Joining the ensemble cast in its second season, he came to "Lost" with more stage experience than camera time, and his previous characters were usually vulnerable and sympathetic "funny guys."

Ben was a character who was delightfully ambiguous, articulate and droll, Emerson said.

"This will be one of the highlights, if not the highlight, of my career," he said. "It's been a great character, and it was a good fit for me as an actor. Some roles you struggle with. This one I seem to always know instinctively how to play."

Emerson's inclination is to return to the stage.

"Part of me doesn't want to get tied up in a long gig right when I finish this long gig," Emerson said. "I kind of want to bounce around."

Emerson calls New York City his home and said he's ready to get back. That's not to say he hasn't enjoyed his time in Honolulu.

"Without even trying I have become involved with the community," he said. "I do charity events and I work with the symphony and I go to schools and talk. In a way, I have become a Honoluluan, but at the same time, it has never felt like my home. I am always conscious of being on location."

"Lost" has survived its run on TV through smart writing that has never failed to keep viewers coming back. But as the show rushes to its finale in May, Emerson expects that many of its mysteries will go unexplained — including one that nags him as well.

As a young man, his character had a friend — a girl — who gave him a carved wooden doll. He has kept it throughout his life. Emerson always thought the "Lost" writers would explain what happened to the girl.

"But I think we are never going to get to it," he said. "I think it's going to be one of those intriguing side stories. A path not taken. That whole notion of paths not taken is central to our show. It's appropriate that we leave some paths unexplored."

Too many answers could ruin the fun that viewers have puzzling over the meaning of "Lost." Emerson believes they'll be pondering its byzantine plot forever.

"It is the landscape of mysteries that is 'Lost,' " he said. "If you explode the mystery, there is no show."