The Frozen we love and know almost didn't happen. If it were not for one big change, it might have cost the studio a mega hit.

Elsa was originally the villain.

Frozen was based on Hans Christian Andersen's "The Snow Queen". When Robert Lopez and Kristen Anderson-Lopez explored Elsa's character so they could write her a signature song. Instead of vilifying her, they couldn't help but empathize with her. Kristen says:

We were still writing a villain song and we started getting into the head-space of what you’d feel like if you were that isolated.

Then they wrong "Let It Go" and everything changed.

According to screenwriter and director Jennifer Lee:

Elsa was going to be the complete antagonist. They kept calling her the “villain.” But there came a point where we said, “We can’t use that word anymore.” You care about someone who’s been forces to hide who they are. Elsa’s not a villain, she just makes some bad choices because she’s in a very difficult situation.

Early sketches show the story revolving around a peasant girl, Anna, who wanted the Snow Queen to freeze her broken heart.

This was how Elsa initially looked like:

Very different from the Elsa we know.

Then they became sisters.

Elsa became good. Or a misunderstood co-protagonist. Lee said:

The issue that kept coming up is, “What do Anna and Elsa have to do with each other? Why does it matter, and how could it matter more?” Someone in the room said, “What if they were sisters?”

Then the whole tone of the movie changed.

Elsa became more the yin to Anna’s yang, as opposed to the bad guy.

The movie decided to prioritize family, instead of just vilifying a character. Good move.