Note: Contains mentions of possible show storylines from Hellblazer. Consider this your spoiler alert, if you haven't read them.

Constantine returns tonight with a new episode that features the character debut of Mary “Zed” Martin (we're not counting her cameo appearance at the end of last week’s pilot). Fans who are familiar with Vertigo’s Hellblazer series will likely know Zed, as she’s been a frequent ally of John Constantine’s since the title’s earliest issues. An artist and fellow magic user in the comic, Zed often helps Constantine in the times of his greatest need.

She’ll be assisting him a lot more regularly on the show as the actress playing her, Angélica Celaya, is a series regular, and along with Charles Halford’s Chas serves as Constantine’s informal team. And the differences don’t stop there. Celaya’s Zed isn’t so much a magic user as a telepath. She gets visions from objects and people that she touches, bringing on some powerful emotional connections and often putting her at odds with Constantine, who tries to avoid all emotional connections.

“John puts up a wall with everything, even with himself,” says Celaya. “No emotion, no nothing. At the same moment, Zed is right there feeling everything. It makes for an interesting confrontation.”

When John first meets Zed, he’s naturally skeptical about her abilities. But he quickly comes to realize that she’s not only sincere, but much like him, carries an otherworldly burden—a storyline from the Hellblazer comics that the show does preserve and will very much allow to play out, provided it runs for long enough.

“They’re going there little by little,” Celaya elaborates. “I think if they were to go full force right from the beginning, that it’s too much. Her family is just too insane and what she’s going through is too much. I mean, come on, giving birth the second coming of Christ is not an easy thing to do!”

Still, fans can expect to see those first divine seeds being sown. Executive Producer Daniel Cerone has stated that he does want to adapt Zed’s most famous storyline, which deals with the aforementioned Second Coming and a religious cult known as the Resurrection Crusade, something that Celaya suggests we’ll start to see in this first stretch of episodes.

“We do touch on it,” she says. “It does get dealt with, and there are some really tough situations where you start learning why Zed has these walls and why she’s apprehensive. Why she’d rather deal with demons than her family. Future episodes are definitely going to touch on the whole hero aspect of Zed making decisions about her particular situation.”

Which isn’t to say that Zed is necessarily a hero. Anyone who knows the character of Constantine knows that his world isn’t a world of absolutes. Things aren’t black and white, and often you’re cheering for very flawed individuals. Zed’s no different.

“She’s not a hero,” says Celaya. “She wants to survive, and she believes that everyone else should have the same opportunities to survive. She believes that they should have the opportunity to change their own destiny. She doesn’t want her destiny. She doesn’t want the weight of that situation on her shoulders. She believes that she can pick and choose what she wants to do and that maybe there’s a higher purpose. And within all that, she questions God a lot, and whether it’s a curse or a blessing.”

Of course, the other thing Zed is known for is her romantic relationship with Constantine. They’re lovers in the book, and there will definitely be elements of that on the show as well.

“There’s definitely lots of tension. Sometimes it might just be a little bit too much,” Celaya says while laughing. “It gets really interesting because there are some things that Zed doesn’t like. not only a dabbler in the dark arts, he’s also a dabbler in women. So maybe Zed doesn’t like that.”

One thing that’s certain is that Zed and John Constantine fans will be treated to a performance by an actress who is clearly 110% committed to the role. Celaya clearly identifies with and relates to Zed as a character, and has surprisingly held a longtime connection to DC Comics, even though this is her first DC role.

“As a normal little girl growing up in the states, all you think about is Wonder Woman,” Celaya shares. “When, I was around 18 years old, I told my mom I wanted to be Wonder Woman . And she said, ‘Mejita, but you haven’t even been an actress!’ At the time, I was studying psychology.

“I just knew that I needed to work with DC Comics. It’s like you put it out there in the universe. I didn’t know there were other female badasses out there, and then I read for Zed, and I see her sarcasm and the way she is into the arts, and how she’s very expressive and creative, very punk and alternative… That’s very me. I see myself identifying with Zed ten times more than I ever would with Wonder Woman.”

How committed to the role is Celaya? Committed enough that she’d even be willing to rock the mostly bald hairstyle that Zed eventually adopts.

“I asked that question. I did! I asked when I was going to be able to shave my head, and they were like, ‘You’re the only actress I know who is excited about shaving her head!’ But it’s the whole situation that happens when Zed gets her head shaven. It’s a dramatic moment, and it makes it much more dramatic when her head is shaven. “

Whether Zed’s in for a massive makeover or not, what’s clear is that she’ll be facing any number of otherworldly challenges and difficult choices throughout the season, and the actress playing her wouldn’t have it any other way.

“You’re getting into the nitty gritty of the comic books, and the gore and action that’s in there,” she says. “It’s awesome. Shooting the scenes, I feel like a kid again.”

Meet Zed in tonight’s new episode of Constantine, “The Darkness Beneath,” airing at 10 p.m. (9 p.m. CST) on NBC.