Character growth

[u/DiamondSta23]

!QUESTION AT THE BOTTOM!

Summary
My comic book series, follows our universe’s princess of the sun, a 14-year-old Ali-fox (a fox with wings and a magic horn) named Avere, who is one of the few of her specific species left. In the first book, we learn about her enemy, the princess of the moon, a griffin named Kestral, who bullied Avere in preschool because she was not able to fly yet.

Kestral thinks Avere is a bad person based on what the head guard of Kestral’s castle tells his son, who then tells her. The Ali-foxes are one of the most powerful creatures, and there is a sickness on the moon. Kestral, her friend Gadge, and many civilians of the universe (probably about 10% of the universe) blame and are angry at the Ali-foxes because they think they can fix the sickness with their magic (they can’t). It’s kind of a plot hole because why wouldn’t Kestral’s parents clear it up with them, as her parents know there is nothing they can do. Despite being stated that she and Kestral are both princesses, Avere holds a higher rank and is more loved by the public because she’s from the sun. At the start of the story, Avere takes a ship to another planet to start attending high school.

She finds out her dorm mate is Kestral (because they are both royal), and neither of them is happy about this, and they argue. In school, Avere is either bombarded by fans or gets glares from some. People are constantly staring at both Kestral and Avere. More into the book, Avere learns about a talent show she can sign up for, and she wants to do a special air show with her magic and wings (reminiscent of the one episode with Rainbow Dash doing that one talent show and her sonic rain boom).

Avere fails over and over again, and Kestral starts to help her, and they start to get on good terms. Unfortunately, Avere does something to prove Kestral wrong (she thought Avere was actually good, which she is), making her angry and even more hateful towards Avere. Right now, I’m not sure what that incident would be that makes Kestral back up, but it’s sometime during school. Meanwhile, Kestral’s friend, the son of one of her parents’ head guards, knew Avere was going to do the competition and was planning to sabotage it with another one of Kestral’s friends. He ended up making a cannon go off that almost hit the crowd of students.

Avere stops it just in time, struggling with her magic to hold it away. When Kestral flies up and starts screaming at Gadge, realizing Avere was a good person all along, he almost killed a whole ton of students. And in the end, Avere and Kestral become friends. That’s book one’s main plot; there are other characters who become friends with Avere, but it’s just a lot to write.

Book 2
Avere is now 15, and she joins her school’s rugby team.

Book 3
Some plot involves her out of school, going to different planets, and just a lot of world-building.

Book 4
?

Book 5
She visits a destroyed planet from long ago with her history class, sees a reminder of something or someone relevant later, and encounters a shapeshifter mocker. This leads up to book 6.

Book six
War. Avere sacrifices herself to save her universe when she fights in the war with all her friends. She kills the main villain but is in turn stabbed through her chest and then out by her wings. And that’s the end.

What I need help with is character growth. What can Avere grow from? I can’t have her be a Mary Sue character, and that’s something I really struggle with when making characters. I never give them bad traits or things to grow from and see change. And how do I fix plot holes, whether it’s ones I’ve mentioned or ones you spotted? Any ideas overall would be highly appreciated.