Robbie Kay didn't even blink before switching sides. After playing the devious and villainous Peter Pan on "Once Upon A Time," the 20-year-old English actor joined "Heroes Reborn" as Tommy Clark, an awkward teen Evo with a mysterious past. It was recently revealed that Tommy was born Nathan Bennet, the son of Claire Bennet, a main character from the original "Heroes" series played by Hayden Panettiere, who did not return for "Reborn." Now, with a solar flare threatening to destroy the Earth, Tommy's power to absorb abilities and manifest them one at a time may somehow be the key to the planet's survival.

Ahead of the remaining two episodes from the "Heroes Reborn" event series -- and, it appears, the last two "Heroes" episodes, period -- Kay spoke to SPINOFF about Tommy's family tree, embracing his destiny and making sacrifices. Additionally, Kay discussed reprising his role as Peter Pan on "Once Upon a Time," and whether his character changed his wicked ways.

SPINOFF ONLINE: Coming into "Heroes Reborn," how much did executive producer Tim Kring map out to you about Tommy's lineage and the importance of the character in the bigger picture?

Robbie Kay: When I first started the project, I think a lot of things were still very much up in the air. There was a lot that wasn't told to the cast. I don't know if that was to maintain a shroud of secrecy or whether there were still things to be mapped out. As you know, everything is subject to change. I had a basic idea of Tommy's character. I knew he was going to be a significant part of the show regardless. With respect to his lineage, when we first started, I didn't know exactly how he was connected to other characters in the show, so that was something I learned further down.

How rewarding was it discovering Tommy's backstory and purpose at the same time as the character?

It keeps it very exciting. Some people argue that it's actually better not to know where your character is going because it allows you to give a more authentic performance. Nobody in real life can predict the future, otherwise it would just be boring. For me, I don't mind either way.

In this case, it was really exciting to see where the character was going. Being a part of that journey really made me more immersed in the whole experience. We got scripts in advance, but it came sporadically. It wasn't like there was a set schedule. It was always a search to find out more information. It made it like a treasure hunt.

What was your reaction when you found out Tommy was actually Nathan Bennet, the time-displaced son of original "Heroes'" Claire Bennet (biological) and Hiro Nakamura (adopted)?

It was crazy to me because I had watched the original show by then. I was very much immersed in that world. To suddenly be playing a character, who has a link to two huge fan-favorite characters from the old show, was really awesome. It added a whole new dimension to the character. When we were filming episodes 7 and 8, where we went back in time, it revealed an awful lot about Tommy's past. That was something I always craved on the show -- the context of what happened in the past and, "What can you tell me about where he came from?" It was nice to be enlightened.

In what ways did Tommy's relationship with Emily (Gatlin Green) help shape him?

I think Emily was Tommy's moral compass from the very beginning. She put a lot of things into perspective for him. Even though she wasn't an Evo, or part of the End of Days thing that was happening, that made it even more real. She was also an outsider in that sense. She was able to sit down and say, "This is who you are. You can't run away from who you are. You are going to have to face your challenges." It was a necessity to have that growth. He really was lost when the series picked up. He was a nobody. To see how far he's come in the span of 11 episodes is astounding. It's been a nice arc to do.

Lately, Erica (Rya Kihlstedt) has been manipulating Tommy and setting him up as this savior. How much does he buy into what she's telling him?

I don't think you can really trust her after seeing guards surrounding her and this evil backdrop. To some extent, Tommy has been manipulated by words. He's been convinced there is an alternate path and that Erica's path is the right path. That's what he's been convinced.

The fact that HRG and other family members have lied to him, especially his mom, it's a lot of things that have been compounded over time that have now finally hit home for Tommy. He stepped back and said, "Wait a minute. Those people have lied to me. Why on Earth should I trust them? Why on Earth should I be on their side and be helping when Erica is giving the facts." There is definitely an argument to be made about what Erica's trying to do.

At this point, he's incredibly conflicted. As we saw in episode 11, some serious facts have now been revealed about Erica, such as her manipulation of Mohinder's and character to spread propaganda. That changes the game a little bit. Moving forward, you're going to see a shift in Tommy's opinion. But, Erica's definitely got into his head. It's given him a lot to think about because she may be right. That's the whole thing. Nothing that she said is necessarily wrong.

"Heroes" culminated its various seasons with all hands on deck against a big bad. How exciting was it to have all the "Heroes Reborn" characters together and their storylines finally intersect?

That was something the cast was really looking forward to. Right off the bat from episode 1, all the cast got along really well. We were all hanging out and having fun. Then, we were joking about how after four or five months, some of us still had never worked with each other. Reading the last few scripts was really cool to see a ton of characters intersect and just to see how they all interact with each other considering they don't know each other. They set it up really nicely with the cars driving to Odessa. It sets things up to be an interesting climax.

Mohinder's voiceover says, "We are defined by our choices." Will Tommy have to make any hard choices and sacrifices, or is it pretty clear cut what needs to be done?

There are still a number of sacrifices and choices that need to be made. The job is not done. The world isn't saved. It's arguably in its worst possible position. Tommy/Nathan is going to have to make a ton of choices and not all of them are going to be great. That's the difficulty he's facing right now. There's going to be a ton of stuff happening in the last episode and not all of it is going to be positive.

On top of "Heroes Reborn," you are reprising your role as the villainous Peter Pan for "Once Upon A Time's" milestone 100th episode in March. How shocked were you to get that call asking you back?

I always though the way Pan went out, there was a possibility for him to return. I didn't exactly rule out returning. It was an absolute joy working on that show, so it was cool to come back into it for a little bit and see the old faces with the crew and hang out with the cast again. It was fun to get back into the shoes of that character after two years. Pan is now being seen in a bit of a different way, in a different light, so it's fun to delve back into that.

Pan and the Storybrooke folk didn't part on the best of terms. Has the Underworld mellowed him out or made him bitterer?

Being in that scenario has given him time to think and reflect on what's happened and time to maybe step back and say, "Maybe I was wrong. Maybe there are different ways to go about things." I think his selfish intentions are still very much there. That's a characteristic that is unavoidable with fans. He's always going to try and find an angle, try and manipulate people into doing things that will eventually benefit him. When we return for the 100th, you'll be seeing a fair bit of that.

Between "Heroes Reborn" and "Once Upon A Time," you've played both the good and bad guy. Which have you enjoyed more?

It's tough because I feel with "Heroes" that I was more involved in the shoot in terms of being there from start to finish. That gave me a lot of satisfaction, the ability to start the character fresh and really develop him. I felt a lot more involved in the process of creating the character. It was a much more hands-on project.

However, it's always fun to play the villain and I absolutely loved it. You get to play around with so much. There's a lot of seriousness with Tommy, which is fun to play as well, but there's something about being a mischievous scoundrel that is very fun.

"Company Woman," the penultimate episode of "Heroes Reborn," 8 tonight on NBC.