Lena Luthor is Lex Luthor's half sister in "Supergirl," which she succeeded him as the CEO of L-Corp following his incarceration as well as a pal of Kara Danvers and Supergirl, her alter-ego. After Monday's episode, the series revealed a shocking reality about Lena and many fans are wondering if she is really an ally.

Kara actually has trust in Lena although it looks like the latter was the one responsible for breaking her adoptive mother Lillian Luthor out of jail. With Lillian being on trial and hated by everyone in National City, Lena appears to only have one ally who trusts that she is not following her family's footsteps as a Luthor.

Despite being a Luthor, Kara is still giving Lena the benefit of the doubt although everyone else in Team "Supergirl" believes that she is just another Luthor. Her well-known brother Lex as well as her mother Lillian attempted to purge the world of aliens as the person in charge of Project Cadmus, which made everyone think that Lena cannot be trusted either way although it is known that she is adopted.

Is Lena really adopted? It appears that it's not the case as Monday's "Supergirl" episode has revealed that she is the illegitimate daughter of Lionel Luthor, which makes her a real and truthful Luthor heiress.

Moreover, reports say that it's unclear whether or not Kara's trust in Lena would be strength or a weakness in "Supergirl" season 2 and some fans worry that Kara might make the same mistake that Clark did. The episode's final scene gave fans uncertainties whether Lena is really harmless as she claimed she is.

Asked whether Lena can really be trusted, showrunner Andrew Kreisberg told Entertainment Weekly that it's going to be Lena's journey for "Supergirl." "She's not adopted, she's actually truly a Luthor by blood, and is it nature vs. nurture?" he said adding that the name Luthor signifies evil.