Science-fiction has always tried to take a position of creating allegories of what we're experiencing in our own environment, and "Caprica" has a very special message it's trying to share, according to its newest guest star, James Marsters.

"Well, I don't want to get too morose about it, but we are much like Rome, you know," Marsters told reporters, including Airlock Alpha, during a conference call Wednesday. "There's something amazingly dramatic in that. But also, it kind of reflects where we are. And you know, it gets pretty depressing if you really go there. But if you talk to climatologists, if you talk to the people who are providing energy for the world. if you talk to the food [producers], you talk to people who are experts on water, fresh water supply, it just gets depressing, you know."

Marsters, best known for playing Spike in "Buffy the Vampire Slayer," isn't saying Earth is necessarily heading down a path of destruction, but "Caprica" provides some of the warning signs just in case we are.

"We, the people who do sci-fi and fantasy, we can address these issues fairly directly because we just change the name and we give you some spaceships and laser guns and robots and stuff, and we can all think about the stuff we don't want to think about, but need to anyway."

Marsters plays Barnabas Greeley on Friday's "Caprica," one of the several disjointed leaders of the Soldiers of the One terrorist group that believes in a single god. His first scene shows him painfully wrapping barbed wire around his arm, making it clear Greeley means business.

"He's living in a time which is coming apart at the seams, just like the Roman Empire did," Marsters said. "And in his world, people are committing human sacrifice and mass executions and mass orgies, friends are shooting each other in the head for fun. And you know, in Rome it was called the Coliseum, and on 'Caprica,' it's called the V-Club."

But no matter what it's called, the psychological effect is the same.

Barnabas is "seeing society rip apart and he sees that the religion is not being helpful in [steering] people towards moral behavior, and so he wants to have a religion with one god that's going to tell people exactly what to do and exactly what the punishment is if you don't do it, and what the reward is if you do," Marsters said. "And that's a very comforting thought and he's willing to try to make a revolution and make that happen, and he's willing to hurt people."

Marsters wouldn't call Barnabas a terrorist. Instead, he sees him as a revolutionary, people who are often misguided, but who feel they are really able to affect change.

The character is expected to air in five episodes this season, with the potential to do more in Season 2, ending just past the mid-point in an episode directed by series star Eric Stoltz. While this is yet another science-fiction project for Marsters, who has appeared in "Buffy," "Angel," "Smallville" and "Torchwood" among other shows, he told reporters he doesn't care if he gets typecast.

He's in love with the genre, and he follows writers. So if anyone like Joss Whedon, or even "Caprica" executive producer Jane Espenson calls him up, he's there.

"If I were playing Urkel, then I'd have a problem being typecast. But when you're typecast as the cool guy or the tough guy or the potent character or the jerk who mixes things up ... I think if you're going to get typecast, that's the one you'd want," Marsters said. "And I really don't have a problem with that at all. I mean, I went into audition for this moon shot thing, I love the Apollo program. I'm a science geek and stuff, so I was just so excited. I would have taken any three roles, you know. But the director was like, 'Oh no man, I need you. I saw you from 'Buffy,' you know, I need you for Buzz Aldrin because he's the rock star.'

"So you know, typecast me."

Will Marsters ever agree to return to play Spike? If it weren't for the whole aging thing, yes. But if he can pull off looking like he did a decade ago, Marsters said he wouldn't miss playing that famous vampire that some people believed a network named for him, for anything.

"It's now been seven years, but I look in the mirror, and you know, I've got to say if I'm rested, I look OK with the proper lighting, I don't know," he said. "But as the years go, I get more and more nervous about that so, you know, I'm thinking well, let's just do a screen test and see if we can light this character so we can actually say, 'Look, I haven't aged.' If we can do that, that'd be cool."

Finally, the reunion between Espenson and Marsters, who both worked together on "Buffy," wasn't as dramatic as one would expect. Especially since the two were in separate countries ("Caprica" is filmed in Vancouver, British Columbia). But that didn't prevent a reunion of a different sort.

"Well, you know what, [our reunion] is exactly like it was on 'Buffy,'" Marsters said. "You know, we communicated through scripts. I like to say that we tried to make love to each other through the scripts, and through the dailies, because I tried to take everything that Jane gave me and then just add my own layer to it so it would be just a little better than she was imagining."

The first offspring from that script love-making premieres March 5 at 9 p.m. on Syfy.

To see a sneak preview of the episode "Know Thy Enemy," click here.