Now in its fifth season, and past its one-hundredth episode, Supergirl has undergone massive development in of itself. When it first aired back in 2015, it was a light superhero drama that was easy to watch and carried lovely messages for the audience to learn from.
Now though, it's still the same show at its core, but it has gotten darker and more creative. The same can also be said for the characters within the series, as almost all of the main cast has evolved and grown. However, there are also those who haven't developed as much as fans might have liked.
Has Grown - Astra
Astra was the main antagonist for the first half of Supergirl's first season. She made for a great villain as her evil plan wasn't so evil; she just wanted to save the Earth from itself. Additionally, her personal connection to Kara Danvers created lots of emotional tension and drama.
Astra was Kara's aunt, and her only surviving family on Earth (besides Superman). Kara spent a lot of her time trying to get Astra to see the error of her ways, and Astra was finally beginning to come around to Kara's way of thinking when she was tragically killed.
Hasn't Grown - Lena Luthor
Arguably, Lena Luthor has grown from who she was when she first appeared on the show. However, she has sort of grown backward. In her debut, Lena made it absolutely clear that she was not part of the infamous Luthor legacy.
She went to quite the extremes to take down her mother, Lillian Luthor and helped Supergirl and her friend on multiple occasions. Recently, though, Lena has started going down a dark path, turning against Supergirl and even forming an alliance with her brother, Lex.
Has Grown - Mon-El
When Mon-El first appeared, he did not leave a positive impression on fans, critics or Supergirl herself. He was rather irritating, and he was just utterly selfish. In all fairness, it must be difficult trying to get used to an alien culture, but he still made a lot of mistakes.
Mon-El was lazy and didn't like working. Instead, he used Eve Teschmacher to do his work for him and then rewarded her by arranging a booty call in a work closet. However, over the course of two seasons, Mon-El matured and became a proper superhero in his own right.
Hasn't Grown - Lillian Luthor
Lillian made her Supergirl debut in the show's second season and looked to be quite a formidable villain. She was head of Project Cadmus, which had previously been established as having been responsible for the abduction of Jeremiah Danvers back in Season 1.
Lillian was, therefore, the main villain for the first part of Season 2, and her relationship with Lena was extremely compelling. However, after a while, Lillian ceased to grow as a character and just when you thought she might be making progress, she reverted back to her former self.
Has Grown - Brainy
When Brainy first appeared in Supergirl's third season, he was an interesting character, to say the least. He was incredibly intelligent, which is understandable, as Brainy is basically a living, walking and talking computer.
However, he didn't have a particularly good grasp of emotions. He felt them but didn't always understand them. Over time, he got to grips with his emotions and thanks to Nia Nal, he even embarked on a relationship with proved to be utterly adorable.
Hasn't Grown - Winn Schott
Winn Schott was the first person Kara came out to as Supergirl, and he was instrumental in designing her first costume. Winn was Kara's best friend until he decided to go to the future at the end of Season 3 to try and help Mon-El and the Legion.
This all sounds pretty remarkable, but the truth is, Winn never actually underwent any substantial development. At the beginning of the series, he was the technical guy, who had a crush on Supergirl. He never really moved past that, ending up as the poor man Felicity Smoak.
Has Grown - Kara Danvers
At the beginning of the series, Kara was a bubbly and cheerful young woman who worked for Cat Grant at her company in National City. She soon became Supergirl and fought for truth, justice, and the American way, just like her cousin.
However, Supergirl was more naive than most Arrowverse heroes and so as the show moved to the CW, Kara began to realize that not everything could be solved with a happy go lucky attitude, and she soon adjusted to the harsher realities of living in the Arrowverse.
Hasn't Grown - James Olsen
For the entire first season of Supergirl, James Olsen seemed to exist purely so that Kara could have an awkward love interest. James didn't really bring much to the table, and his awkwardness with Kara was pretty difficult and annoying to watch at times.
Although James did become a hero in his own right, when he donned the mantle Guardian, his development came to a halt during Season 2. While his last episode did give him something else to fight for, his character was a missed opportunity.
Has Grown - Alex Danvers
Alex Danvers is Kara's put-upon adoptive sister, and she's been through an awful lot so far. In the first season, she had to deal with her mentor and father figure, Hank Henshaw, as he revealed that he was actually an alien from the planet Mars.
However, her biggest character development by far came in Season 2, when she struggled with her sexuality. She had caught feelings for Maggie Sawyer, who encouraged Alex gently to come out as gay to her family and friends.
Hasn't Grown - Cat Grant
First of all, Cat Grant was an amazing character, and she certainly helped the first season of Supergirl to no end. Cat was the head of CatCo, and also she was in charge of Kara, Winn and James, three of the show's main characters.
Cat had a vicious tongue, but a warm heart and she was liked by fans and critics. However, she never really got time to develop on the show, as she left early on in Season 2. If only she had stayed, who knows what might have become of her in later seasons.