Zachary Quinto, <i>Heroes</i> Zachary Quinto, Heroes

Well, folks, Heroes has done it again. Nathan Petrelli may have expired with a glorious, gurgling coda, but his character lives on — thanks to Matt Parkman — reincarnated inside a mind-wiped version of arch-villain Sylar. While the closing moments of the Season 3 finale suggest that Sylar's presence still exists in "Nathan," have we seen the last of the furry-browed Sylar (Zachary Quinto) we've always known?

"Zach's not done," Adrian Pasdar tells TVGuide.com. "There's Nathan, there's Sylar, and there's the point of view that you have to factor in. If I look up into the mirror, who would I see?"

Naturally, the twist sets up an epic internal battle between Nathan and Sylar in Season 4. "Who's going to be able to control the actions of the body?" Pasdar teases. "Like one of those computers that self-teaches, the longer he stays in my body and the longer he assimilates my physical structure and DNA, the more control I get. So it becomes a battle of who's in charge."

Pasdar says when he first learned that his character was going to "die," he was thrilled. "I wanted to try something new with Nathan, with the idea of the character," he says. "And I think they've found a much more interesting way to engage. It's much more interesting for me to play what's coming up than anything I could have imagined without dying."

As long as Sylar exists, however, the heroes will have problems. And now, they have Parkman — and master manipulators Noah Bennett and Angela Petrelli — to blame. Greg Grunberg says keeping this dirty little secret will present its share of problems next season.

"You've got an alliance right now with the three of us, but Angela Petrelli is not to be trusted. And you don't want to get on her bad side," Grunberg says. "I did what they asked me to do, and now they're going to ask me to do more and get in deeper. It's going to be a spiral that is going to tear my character up. It leads me to believe that next season is just going to be awesome."

No matter how "awesome" next season could be, will fans stick around? After all, the death producers promised would stick has technically been unstuck. Pasdar says he's not worried.

"Some things should stick, otherwise there's no weight if you're going to reset everybody's history every 10 minutes, and nobody's going to pay attention anymore," Pasdar says. "But as fascinating as concepts might be, ultimately it's people that engage viewership. If you're going to ask people to tune in week to week, you want to follow somebody's plight, not some nameless story arc. We've tried to be consistent — sometimes you win, sometimes you lose. But I think we're going to come out on top."

Pasdar also hopes Nathan's path crosses with the returning Tracy Strauss, who, with a revenge mission driving her, could become a major Season 4 villain. Grunberg, on the other hand jokes that he might have evil intentions of his own.

"Only Parkman knows truly how to control [Sylar], so it would be cool if I could unleash him," he says. "I could tell HRG and Angela everything is OK, meanwhile I unleash the monster. I don't know why I would do it, but maybe if I get pushed to the point where I just can't take it any more, I let the monster out."

What would you like to see happen in Season 4?