IN THE PAST FEW YEARS, writer Zack Whedon has been kicking ass and taking names—big names like John Connor, Kyle Reese, and most recently Shepherd Book, an enigmatic character from his brother Joss' TV show Firefly. In comic book adaptations of stories set in the Terminator and Firefly 'verses, Whedon's writing has the tone and resonance of the originals, while giving readers interesting new stories about beloved franchises. In his recently released comic Serenity: The Shepherd's Tale, Whedon expands on the mysterious past of Shepherd Book, while his most recent run of Terminator comics, The Terminator: 1984, just wrapped up with a stellar new take on the Terminator story. Whedon took some time from a busy schedule to talk about his growth as a comic book writer, and to (rightfully) slag on Terminator Salvation.

MERCURY: How is it writing for characters that weren't originally yours?

ZACK WHEDON: It's a challenge, you know, and you don't want to screw it up, because people know all these characters already. It's a little bit intimidating in that regard, but working in television, you sort of need that skill to write in other people's voices, so it's something that I've had practice at.

Did you feel constrained by the short length of The Shepherd's Tale?

You can tear through it really quickly, but if you go back you can take your time with it. The art is so beautiful. And because I had to make really tough decisions about what I kept and what I lost, I really feel like every panel feels essential.

I interviewed you in 2008 about a web comic you wrote about Captain Hammer. How have things changed since then?

Yeah, that was the first comic I ever wrote. I'm still learning a lot... learning about the pitfalls of the medium and what not to do and what works and what doesn't. With Terminator, I got to tell a story over a longer period of time, and that taught me a lot. That's a totally different discipline than writing something that is contained in eight pages.

I love your original character, Ben, in the Terminator books.

There's a lot more freedom when you can create someone's voice. I love that character. I think [Ben is] a guy who because of the horrific nature of his life is perpetually looking forward, because to look back is too painful. That sort of defines him—he's always forward moving and an optimist. He doesn't dwell on the tragedies of his life.

What was your philosophy about echoing the original stories?

With Terminator, I did a lot of thinking about what has gone wrong with [the franchise]. One of the reasons the fourth Terminator movie doesn't work as well as the other ones is because, essentially, the structure of those first movies is the same—one person is sent to attack and one person sent to protect. And go! When there are many, many Terminators, they become less scary. The thing that's terrifying about a Terminator is that you can't kill it, it never ever stops. It just keeps coming and coming and coming. So you have to sort of know that Terminator, to be able to identify it and fear it. When there's just a sea of them, it takes away that horror element. With 1984 I tried to get back to the "one machine that won't stop" construction.

Click here to read our complete interview with Zack Whedon.