Though she was introduced just last year, Lena Luthor has quickly become an important part of Supergirl. The scientist and budding mogul made fast friends with Kara Danvers and has even publicly shown her support of Supergirl, despite her brother Lex's infamous vendetta against Superman and her mother's hatred of aliens. Though Lena and Kara had their ups-and-downs over the course of Season 2, their friendship remained steadfast right up to the finale, where Lena was forced to release lead into the atmosphere and banish Kara's Daxamite boyfriend Mon-El from the planet. At Comic-Con International in San Diego, Supergirl actress Melissa Benoist and Katie McGrath, who plays Lena, teased that there may be some changes in store for the two unlikely friends in Season 3.

"I think Luthor and Super relationships are always the most interesting stories in a Super comic," Benoist shared. "I think, especially with Lena and Kara and how close they are, how they relate to each other as women, what they've been through with their families, what they've lost, is a really strong foundation for that connection. So I'm excited to see where it goes. It's precarious, too. It's kind of teetering on a really small ledge."

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"Do you think she's ever going to figure out the truth? Don't you kind of want her not to, though? Part of the magic of the show is there's got to be one person who believes they're two different people, even though they're exactly the same," McGrath mused. "Everybody else knows! Isn't it nice to have one person who's the complete fool? Do you know what I mean? It's the magic of the comic book show, is that people don't know that Kara and Supergirl are the same person. If everyone believes it, then how can you disbelieve it, if that makes any sense? So I kind of don't want Lena to find out!"

Asked if there would be any tension between the two in Season 3, McGrath said, "I think more, actually, Lena feels guilty, more guilty because of what she did to Mon-El. So, when it comes with her relationship with Kara, she's very worried the fact that she played a part in sending Mon-El away has damaged her friendship with Kara because, for Lena, the most important relationship she has at the moment is with her best friend, because her mother is, you know, crazy and disappointed her again. So her relationship with Kara is very important, and her relationship with Supergirl is more of a respect and more of a 'you are our savior and I think you're amazing,' but it's a true friendship with Kara. So I think that's where it starts at Season 3, but where it ends up? We've got a whole lot of episodes to figure it out. It's going to change. It has to."

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McGrath also posited how Lena would react to finding out that Kara was Supergirl all along. "See, this is the number one question I get asked, and I've been thinking about it. You know, I don't think she'd have a problem at all with her being an alien. I think she'd have a problem with her best friend having lied to her," she explained. "I think that's going to be the issue if it ever happens, is that 'I don't care who you are! I care that you didn't trust me. You're the same as everybody else. You didn't trust a Luthor. You always told me you did.' And I think that would be difficult for her, because you've seen that Lena doesn't have a problem with aliens. I think her best friend lying to her and treating her… she discovers that she thinks that… that would, I think, break her."

"I think I'm sort of cursed with being a Luthor, but in a way that makes it kind of interesting because you're not just one note," she added. "You're not just the good guy. The best characters are flawed, and the best characters are the bad guys with hopes of redemption and the heroes with a dark side. So, to be able to do that for me and as an actor and I think as a viewer, it's the most interesting thing. So people want to believe I'm eventually going to become bad? I'm like, 'Alright! I'll show you're wrong, or I'll prove you're right.' Who knows?"

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As to her favorite part of Lena's friendship with Kara, McGrath said, "About how supportive they are of each other. I mean, I know me and my best friend -- I don't know about any of you -- but if my best friend rang me up and was like, 'I murdered a puppy,' I'd be like, 'Puppy deserved it.' You know what I mean? It's that kind of thing. It's that, in their eyes, they can do no wrong and I think you don't get that a lot in TV. You don't get the idea of proper females supporting each other, not being catty, not being bitchy and not having any other agenda other than 'I just want you to be okay.' I think that, for me, is the most important part of their relationship is that it is about the other person just wanting you to be alright, and whatever I can do to do that."

Executive producers Jessica Queller and Robert Rovner also confirmed that Lena's struggle with her family's evil legacy will continue in Season 3. "We love having Katie [McGrath] as a series regular this season and she'll be more central in the show, but I think one of the central issues about Lena is that she comes from this family of bad guys and I think her journey is -- and we've see her grapple with it in Season 2 -- is she on the side of good or is she on the side of bad?" Rovner explained. "So we'll continue that journey with her this season."

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"Will she fulfill the evil legacy of her family name? Is she like a ticking time bomb?" Queller added. "We'll see which way she's going to go."

Returning to The CW on Monday, October 9th at 8 p.m. ET/PT, Supergirl stars Melissa Benoist as the Girl of Steel, David Harewood as Martian Manhunter, Mehcad Brooks as Jimmy Olsen, Chyler Leigh as Alex Danvers and Jeremy Jordan as Winn Schott, with appearances by Calista Flockhart as Cat Grant and Tyler Hoechlin as Superman.