The Commoner Girl Wants to Correct the Rainbow Villainess!

I woke up in the world of an otome game. In the game, I was supposed to be an extremely arrogant villainess with a louder voice, greater pride, and more presence than anyone else, looking down on everything except herself. Apparently, I've become a commoner girl who is her childhood friend. She dies in every ending regardless of the protagonist's route—the only thing that changes is how tragically she dies. However, unlike in the game, she is kind to me, a commoner. Fond of her, I decide that I won't let her become a villainess, and if possible, I'll correct her loud voice! But gradually, something strange starts happening to her...?