Supergirl is redeeming Lena Luthor in its final season. Lena has been an integral part of the Arrowverse series since season 2. She forged a friendship with Kara Danvers and worked with Supergirl, not knowing they were both one and the same. In Supergirl season 5, Lena landed firmly in the gray area of the good vs. evil debate (a staple of the superhero genre) when she created a program that could manipulate the minds of people. However, Lena took a big step towards a proper redemption storyline in the second episode of season 6, called “A Few Good Women.”
Lena had good intentions regarding her experimentation and research with Q-Waves — which would have quelled the aggressive, violent parts of human minds and made them peaceful and docile — but she misused and abused the power that came along with it in her attempts to control people. It created even more tension between her and Kara and exacerbated the distrust that already existed between them. Things got worse when Lena stole the Myriad program from the Fortress of Solitude in an attempt to amplify the Q-Wave frequency that would alter people’s minds on a global scale. “Crisis on Infinite Earths” changed some of these events, with Myriad remaining inside the Fortress of Solitude. However, Lena continued working on her research in the post-"Crisis" era and tested it on prisoners with the assistance of Lex Luthor.
In Supergirl season 6, Lena has since reconciled with Kara and made amends for her actions privately. But, by taking the stand during Lex’s trial in “A Few Good Women,” Lena is taking actionable steps towards true redemption. She didn’t have to be a witness in Lex’s trial. In fact, she had no desire to do so, especially knowing she would possibly incriminate herself by admitting to her own actions during Supergirl season 5 and judged for it by the court of public opinion and the law. However, Lena took the stand anyway because she knew it was the right thing to do.
By taking responsibility for her own brainwashing actions from season 5, even if it was in an attempt to put Lex in jail for his crimes, Lena was truly atoning for her sins. She’s doing the work to make things right and that is an important part of a redemption arc. Without accountability, Lena’s actions might have been swept under the rug. However, Lena has never shied away from trying to do good and outing herself for the similar crimes of her brother, whatever her goals were, is crucial in absolving herself completely. It also makes her a much better person than Lex could ever hope to be. So often certain actions and crimes are easily forgiven in the Arrowverse, sometimes glossed over completely.
Through Lena, however, Supergirl is showcasing how easy it can be for someone, despite their good intentions, to travel down a dark path of righteousness. After all, it’s not like Lena didn’t know what she was doing; she made some questionable choices in the name of doing something she believed would help people but would actually cause more harm. Lena made an active choice to take accountability in the final season of Supergirl, even if that means she’s now being investigated for what she confirmed she did. That takes guts and bravery to face the public in a way that would paint Lena in a negative light, but she went and did it anyway. Lena is making an effort to right the wrongs of her recent past, and that is a tremendous feat and a step in the right direction.