Elsa is an accidental antagonist in Frozen when she plunges Arendelle into winter in the middle of summer. Until she learns how to control her ability to manipulate ice and snow, she's viewed as someone dangerous by nearly everyone other than her little sister. That's not entirely her fault though, and she's truly a heroic individual who overcomes her own hangups.
Elsa helped to usher in the trend of modern Disney princesses not having love interests and embracing their own strengths and weaknesses. She doesn't need someone else to save her, but she does rely on the support of her sister to begin her journey to hero.
Elsa Understands Fear Leads To Hatred
"Fear Is What Can't Be Trusted."
When Elsa gains access to ice memories of her grandfather in Frozen II, she's grown a lot. She understands that fear of her own power is what caused so much of her trouble in the first place, so she rejects her grandfather's idea that fear is exactly what people need.
Despite Elsa initially giving in to her own fear, she understands that fear of the things she doesn't understand can only lead to more heartache. For her grandfather, it leads to mistrust and hatred, and Elsa and her sister have to work to fix the mistakes he made, which is nearly impossible.
Anna Knows Elsa Takes The Heroic Actions First
"If You Don't Want Me To Run Into Fire, Then Don't Run Into Fire."
Elsa spends a lot of time worrying about her little sister Anna's safety. It's ingrained in her from a young age when she accidentally uses her power against her. As a result, she wants to keep Anna out of the line of fire, or ice as the case may be, no matter the cost.
That means that Elsa spends a lot of time running into danger, then admonishing Anna for doing the same. Anna points out, however, that if her big sister wasn't putting herself in dangerous situations, Anna wouldn't be doing the same. Elsa inspires Anna to do just as much good as she tries to do.
Elsa Takes On The Responsibility Of The Past
"I Promise You I Will Free This Forest And Restore Arendelle."
Elsa doesn't have to try to repair the damage caused by her grandfather but she does though. When she learns the part her grandfather played in tricking the Northuldran people into allowing a dam to be built that would divert their resources, Elsa wants to help them.
She doesn't just feel the responsibility to her own kingdom, but to the people that share its space. Elsa takes a step to give Northuldra its freedom back after it has been trapped behind the enchanted mist and a dam for years. It could have cost her and her sister their own kingdom, but Elsa commits to finding a way to make it work.
Anna Has Complete Faith In Elsa
"I Believe In You Elsa, More Than Anyone Or Anything."
A lot of heroes become heroes because they believe in themselves even when others don't. Elsa has a lot of doubts about herself, but one person who doesn't ever doubt Elsa is Anna.
The unconditional support of Anna is part of what allows Elsa to keep going even when she's not sure she can actually find a solution to her problems. Anna's support is what allows Elsa to believe that she could be a hero one day.
There Is Strength In Ice
"...Stronger Than One, Stronger Than Ten, Stronger Than A Hundred Men."
Frozen opens with a group of men separating blocks of ice over the river and carting them back to Arendelle for sale. The song they sing is about ice itself, not Elsa, but their sentiments still apply.
Elsa, after all, has the ability to manipulate ice as she sees fit, creating snowstorms, freezing the ground under her feet, and building a palace from nothing more than frozen water. In all that ice is strength and power. Elsa might not see it at first, but the men in charge of selling ice do.
Elsa Resolves To Be More Open
"...We're Never Closing Them Again."
Anna and Elsa's parents originally close the castle gates to limit Elsa's exposure to others while she learns to control her powers. At the time of their deaths, she still doesn't have enough control for her to want the gates open.
When she embraces her power though, Elsa also resolves to be more open about who she is. That might not seem like a particularly heroic decision, but for a person who was completely cut off from the outside world for years, opening herself up to the people of Arendelle is a potentially scary decision.
Elsa Puts Past Disney Princess Decisions Into Perspective
"You Can't Marry A Man You Just Met."
Anna develops feelings for Hans as soon as she meets him, but that relationship eventually sours when she learns the truth, proving that Elsa was exactly right when she told her sister marrying him was a bad idea. Anna was ready to tie the knot after only knowing him a few hours!
Elsa's decision to tell her sister she couldn't marry Hans is a completely different turn than previous Disney princess movies. Most of those involved a princess getting her happily ever after with a prince she'd only met when he saved her life. Elsa sees the flaw in that idea and how badly that particular situation could go for her sister. The audience loves her for it. By saying no, she saves Anna from a loveless marriage and a potentially treasonous claim on the throne.
Elsa Embraces Mistakes
"That Perfect Girl Is Gone."
"The cold never bothered me anyway," might be a better remembered line from "Let It Go," but it's not as heroic as embracing imperfections. Elsa spends her entire childhood trying to be the perfect person her parents encourage her to be. She does it for so long that she lives in fear and stifles her true self.
It's not until Elsa literally lets go of all of those imperfections that her power is at its height, allowing her to pull an ice castle out of the snow. Perfection is unattainable, and it's important for even the best heroes to realize that.
Elsa Allows Herself To Grow
"Step Into Your Power. Grow Yourself Into Something New."
When Elsa sings these words, it's because she's following a voice that she thinks will lead her to another magical spirit. She's encouraging the voice to allow themselves to grow, but little does she know, she's actually the fifth magical spirit.
Her lines in the song go from encouraging someone else to encouraging herself to be the person she's meant to be. Though it's reiterated throughout both Frozen movies more times than the audience can count, Elsa's story is all about embracing her own power instead of allowing it to make her afraid. Only once she does that is Elsa able to save her sister, end the seemingly endless winter, and help Northuldra and Arendelle both.
Elsa Isn't A Hero Alone
"A Bridge Has Two Sides. Mother Had Two Daughters. We Did This Together."
While Elsa often runs headlong into danger on her own, the audience has to acknowledge that her heroics don't exist in a vacuum. She might have the power to make things happen, but she can't be in two places at once, and sometimes, she needs a little help.
Even Elsa can admit that. She points out that when she helps the people of Northuldra, she doesn't do it alone. Elsa credits Anna as the other side of the "bridge" that brings their communities together, and she's not wrong. It's big of her to admit that she might need help since she spends so long avoiding it.