i just reread that part, it seems she's the original author and the game company/publisher changed alot from the original story. it's kinda messy tbh, when Phil saw her memory she just came from buying the book and talking about how it's different from what she wrote and she got hit by truck-kun. even if her life was unfortunate, she's still a btch for trying to ruin MC's life and she doesn't see the people there are "human"
I read a spoiler saying she's a fanfic author, she wrote the story based on the game and the company took a liking to her work so they decided to publish it
She's not the author, and the Phil in the game didn't suffer or anything when the ogmc came to the castle became friends with our mc and she got to know her family and live with them peacefully but this psycho went and wrote a weird fanfic where she needed a villain
And this life is going according to the game not the novel
Not sure if it's correct or not but looks good to me and the most convincing spoiler out of all the ones I read lol
She's really a shitty person for the way she thinks. I've seen similar plots where the mc thinks about how it's fine when the characters get hurt or something bad happens to them since it's just something the mc read/play. The only good thing about those type of stories is how they realized that each and every one of the characters are actually their own person as the story flowed.

Is the one possessing Ellensia really the author?? I'm a bit confused