The series stars Melissa Benoist in the titular role of Kara Zor-El / Kara Danvers / Supergirl, as well as Mehcad Brooks, Chyler Leigh, Jeremy Jordan, David Harewood and Calista Flockhart, with Katie McGrath, Chris Wood, Floriana Lima, Odette Annable, Jesse Rath, Sam Witwer, Nicole Maines, April Parker Jones, Azie Tesfai, Andrea Brooks, Julie Gonzalo, Staz Nair, LaMonica Garrett and Peta Sergeant joining in later seasons.
By the end of season six following Lex Luthor and Nyxlygsptlnz being dragged into the Phantom Zone, Kara finds out that Cat knows of her secret identity and is convinced to reveal it upon accepting the position of editor-in-chief at CatCo.
[5][6][10] Among his reasons for moving across the country include his breakup with his girlfriend Lucy Lane (with whom he has since reconciled),[11] and keeping an eye on the newly revealed Supergirl for Superman, who considers him a close friend.
A brilliant scientist with a past as a party girl, she was hired by Hank Henshaw at the DEO after being arrested for drunk driving, in an effort to turn her life around and see potential in her.
Winn has an unrequited crush on Kara and is rivals with James for her affection, and he later pursued a relationship with Cat's new assistant Siobhan Smythe until she turns into Supergirl's supernatural metahuman archenemy Silver Banshee.
In addition to remain improving Kara's costume and offers her tech support, Winn also makes his own modifications with her interdimensional extrapolator, a device she received from Earth-1's metahuman inventor Cisco Ramon.
J'onn takes Henshaw's likeness to reform the DEO from within as well as a promise to Jeremiah Danvers to watch over Alex and Kara, who each subsequently trust him as a mentor after learning of his true identity.
Lena makes an Anti-Kryptonite suit that wasn't on Earth-Prime so that Supergirl can fight Rama Khan, Tezumak, and Sela who are empowered by Kryptonite while also rescuing William Dey from Eve.
After returning home, Sam remains a devoted mother to Ruby with no memories of her actions as Reign, while her Kryptonian alter-ego becomes a black-clad, masked vigilante who murders those she sees as evildoers.
After winning a debate against Kara Danvers on national television, Ben is given his own weekly show named "The Lockdown" whilst secretly operating as the masked Agent Liberty.
Starting to fall ill from the experimental serum and no longer having any reason to his goals, Ben attempts to take revenge on Lex for manipulating him but is ultimately stopped by Kara, Alex Danvers and James Olsen.
[40][41] Andrea Rojas (portrayed by Julie Gonzalo as an adult, Alexa Najera as a teenager; seasons 5–6) is the CEO of Obsidian Tech, an old friend of Lena Luthor, a former girlfriend of Russell Rogers, and the new editor-in-chief of Catco Worldwide Media who Kara Danvers and James Olsen dislike.
During his investigation, William arrived at a warehouse and was unable to find any proof of Lex's latest plot due to Margot Morrison using a cloaking wall to hide herself and those who got trapped in virtual reality.
Near the end of the season, Andrea breaks into Lex's mansion, steals his personal journals and publishes a revealing article on them under William's name to increase CatCo's viewership.
After allowing Nia's mother to be revived for a day, Nyxly ran into the hunter Mitch and collaborated with him in a plot to trap Supergirl by having Dr. Desmond Raab build a cryo-bomb.
It is later revealed that Astra and Non created Myriad, a mind control program that is designed for the purpose of saving the environment but can also be used to enslave people, and hence, is the main reason they are sentenced to Fort Rozz for life.
Barry Allen / Flash (portrayed by Grant Gustin; seasons 1–5) is a crime scene investigator from Central City on Earth-1 who becomes a superhero speedster after being hit by dark-matter infused lightning.
In season two, Barry and his fellow heroes from his Earth recruit Kara to their universe to help fight against the Dominators, an armada of alien invaders who attack their world due to their fear of superpowered beings.
[52] Non (portrayed by Chris Vance) is a former scientist in league with the House of El and a brutal Kryptonian military officer who is sinister, powerful, and angry – the antithesis of all things Supergirl stands for and becomes her greatest threat.
[56][57] In addition to her duties as trial counsel (prosecutor) for the Judge Advocate General's Corps, United States Army (where she held the rank of major), Lucy is a legal attaché on her father's staff, though she resigns her commission to remain in National City.
However, when Kara reveals to her that she is Supergirl, she helps rescue Hank and Alex, and is later named acting director of the DEO[60] By the end of season one, Lucy officially becomes a co-director with J'onn J'onzz after he returns to the DEO Leslie Willis (portrayed by Brit Morgan; seasons 1–3) is an abrasive, and funny shock-jock who works for CatCo and becomes as dangerous and shocking as her words following an accident[51][53] in which Supergirl rescues her from a potential helicopter crash during a lightning storm.
Sam Lane (portrayed by Glenn Morshower) is a powerful military general and overprotective father to both Lucy and Lois whose arrival in National City stirs up trouble for Supergirl when he enlists her in a dangerous government initiative.
[64][65] Near the end of season one, Superman proves vulnerable to Myriad's mind control, as Maxwell Lord put it "watched Sesame Street and went to preschool; nurture over nature".
In the present, it is revealed that Lex secretly watches and orchestrates a series of events including Ben Lockwood's leadership to Children of Liberty and Red Daughter's alignment with the rogue nation Kasnia.
After helping to avert said Crisis and assisting in rebooting the multiverse, Lex regained control of LuthorCorp, became the head of the DEO (now a subsidiary of his company), as well as a hero in the eyes of most of the newly created Earth-Prime's people.
From day one of Earth-Prime, Lex had manipulated Eve Teschmacher into being his inside person in Leviathan where he had her orchestrate the events caused by Amy Sapphire and Richard Bates as well as tricking her into killing Jeremiah Danvers.
While Supergirl was preventing a Sun-Eater released by a Morae on Leviathan's side from eating the Sun, Lex went to the scene of where those who were trapped in virtual reality were being held and freed them while killing Margot.
In season six, Lex Luthor goes a head with his next phase of his plan by having Lillian copying the powers of the Leviathan members into him and beginning a broadcast that would harm those that don't have Obsidian Platinum lenses.
In season three episode, "For Good", Lillian later targets Morgan Edge after he poisoned Lena which leads to both of them being defeated by Supergirl and Jimmy Olsen and arrested by the authorities.
Gamemnae (portrayed by Cara Buono) is a high-ranking Leviathan member with technokinesis, electrokinesis, and the ability to assume a metallic form who came to Earth from Krypton's sister planet Jarhanpur during the age of the dinosaurs.