The slogan "Trust No One" applies to more than just "The X-Files." In season one of "Marvel's Agents of S.H.I.E.L.D.," the team was blindsided and betrayed by their teammate Grant Ward (Brett Dalton), as well as long-time agent and main character Phil Coulson's (Clark Gregg) friend, John Garrett (Bill Paxton). Both secretly served Hydra and were instrumental in S.H.I.E.L.D.'s dismantling.

Now, to rebuild the organization and to continue to confront major threats, Coulson -- now director of the new S.H.I.E.L.D. -- has added to his ranks. One new recruit is Isabelle Hartley (Lucy Lawless), a mercenary agent who has a history with Coulson. Seen most recently as Ron Swanson's love interest in "Parks and Recreation," Lawless has an especially storied career in genre television, including her starring role as "Xena: Warrior Princess," plus the acclaimed "Battlestar Galactica" revival and multiple "Spartacus" series.

RELATED: Marvel's "Agents of S.H.I.E.L.D." Keeps It Sinister In New Poster

Days before the second season premiere, Lawless spoke to CBR News about Isabelle's introduction, history with Coulson, playing the "badass" character, reuniting with "Spartacus" writers (now "Agents of S.H.I.E.L.D." showrunners) Jed Whedon and Maurissa Tancharoen and the many unique actor names (including Reed Diamond and Nick Blood) populating the show in the second season of the ABC action-drama.

CBR News: "Agents of S.H.I.E.L.D." producers Jed Whedon and Maurissa Tancharoen worked with you on the various "Spartacus" series. Did they just call you out of the blue and offer you the role of Isabelle Hartley?

Lucy Lawless: Yeah, they did. They had already written terrific stuff for me on "Spartacus: Gods of the Arena," and "Blood and Sand." I was very thrilled to work with them again. And, of course, with Marvel, which is part of the Comic-Con family that I have spent so much of my career with. It was a wonderful way to get back to my Comic-Con roots and to my fans, who are so steeped in that world.

From your discussions with Jed and Maurissa, what was your sense of who Isabelle was, and what attracted you to the character?

Well, she's a badass girl. You don't want to mess with her. I was very interested in the fact that she's a mercenary. I quite like people who have a lot of duality. You try to play them as somebody perfectly sensible and likeable, but who does terrible things for a living. I was attracted to that. She's a dangerous gal.

Obviously, Isabelle was not seen last season. What brings her out in the open now?

Well, Coulson brings her back. They have a long history. She's one of his most-trusted agents, so they've got to defeat the forces of Hydra and rebuild S.H.I.E.L.D. They have to rise from the ashes and collect everybody together because they are the only ones capable of going against the growing power of Hydra.

What does Isabelle add to the team?

She's somebody Coulson can trust, because they've been stung badly by Ward. She's somebody they know can get the job done.

What do you enjoy about the way Isabelle is introduced in the season two premiere?

I personally like being part of the team. She's got this younger agent, named Lance Hunter, who is played by Nick Blood. He's going to blaze across your screen. They are bringing in some more hubba hubba for people who like that sort of thing. He's also a fine actor.

There are all these great names on set. There's "Reed Diamond" and "Nick Blood." "Lawless" is a cool name, still.

In the teaser clip, there seems to be tension between Isabelle and the other agents during a sting operation. Does she play well with others?

Some. [Pause] She's like a grumpy dude. She knows how to put the team ahead of her own needs, that's for sure. You'll see how that plays out.

First "Agents of SHIELD" Season 2 Clip Teases New Mysteries

Isabelle knows how to wield a gun. Does she have any cool toys like Coulson?

I haven't seen any cool toys yet. Maybe the next episode. I'm going to ask them to write that in for me. If Coulson has cool toys, I deserve some cool toys. Show some respect.

How many episodes have they locked you down for?

It's unlimited. Whatever their imagination can come up with. I can't talk about all these things or I get in trouble.

Back in your "Battlestar Galactica" days, you wanted a character with a significant arc. How important is that to you now?

It's hard to say with writers. They want to see how the audience likes the character. I don't know. How important is that to me? It depends what the commitment is. Sometimes you take a job because it's with great people and a great location. It's like, "Yeah, I totally want to go to Bolivia." And sometimes you do things for the fans. We'll see what happens with Izzy. She's got quite the backstory.

Viewers keep hoping "Agents of S.H.I.E.L.D" will incorporate even more of their favorite Marvel characters. Do you have a wish list too? Are there any heroes or villains that you want to pop by?

I'm already psyched about The Absorbing Man. We all remember him from the comics when we were kids. It was such a cool idea, even in the two-dimensional format. You felt the ultimate potential for danger from this character. For me, that blasted me back to being 8 years old. And we always like female villains.

I think we just need a whole lot more of Izzy Hartley, really. I also want to see Patton Oswalt's character (Billy Koenig) with octopus tentacles or something.

Lucy Lawless makers her "Marvel's Agents of S.H.I.E.L.D." debut on the second season premiere, 9 p.m. Tuesday, Sept. 23 on ABC.