Lena Has Words With 'Supergirl' in New "The Fanatical" Clip

Team Supergirl may have captured Reign, but the Girl of Steel and Lena Luthor are still having major differences of opinion on how to deal with her in tonight's upcoming episode "The Fanatical."

In a new clip for the episode, Lena (Katie McGrath) attempts to inject or insert what appears to be Kryptonite into the Worldkiller but is unsuccessful and as you can see in the video above that reignites tensions between Supergirl (Melissa Benoist) and Lena.

When Reign (Odette Annable) starts threatening to kill Lena and then destroy Earth once she gets free, Lena blacks out her containment unit as she has come up with technology that is impenetrable by Kryptonian x-ray vision. Trying to look through it is also painful for Kryptonians and that's enough to set Supergirl off on a mini-lecture about Lena and her anti-Kryptonian measures. This time, though, Lena is simply not having it.

"I told you about Kryptonite and I will tell you if I make it again because I agreed to that, but in regards to other things I work on, this may come as a shock to you, but I don't think about you while I'm doing it," Lena says.

The exchange is particularly difficult because, as fans of the show know, Lena and Supergirl's alter ego, Kara Danvers, are best friends. With Lena having so much animosity towards Supergirl, Kara is in a difficult position and, according to co-showrunner Jessica Queller, it's something that viewers will see more of as the season continues -- especially now that Supergirl and Lena are working together to save Sam.

"One thing that we play a lot with in the upcoming episodes is the triangle between Lena, Kara, and Supergirl, because Lena has a very different relationship with Kara Danvers than she does with Supergirl," Queller recently told TV Line. "Something we had never played before that we are really examining and excited about in the upcoming episodes is that Lena and Supergirl are at odds about certain things and a bit angry with one another, but Lena and Kara are best friends. Lena feels the closest to Kara of anyone in the world, so then Kara is suddenly in this position where is sort of living two lives with one of her best friends. And although we've always had to see Supergirl maintain a dual identity, it's very personal when it comes to Lena, and it's very challenging for Kara, and so we're really interested in that dynamic."

Unfortunately, the tension with Lena isn't the only challenge Supergirl faces in "The Fanatical". The team will get some help from an escapee from Thomas Coville's Cult of Rao and while it may get them closer to saving Reign, it will also present a new concern when Supergirl discovers that the cult is no longer worshipping her but have, instead, turned their devotion to Reign.

Supergirl airs Mondays at 8/7c on The CW. "The Fanatical" airs tonight, May 21.

Do you think there is any way the relationship between Supergirl and Lena can be salvaged? Let us know in the comments!