TotallyNotNyx

@Princess of Bolts ⚡🔥⚡ - I think one of the articles of faith we see in the EqG universe is that anyone overwhelmed by Equestrian magic changes into a worst case form of themselves and start acting out their deepest desires, however base they may be.

Once Demonic Form Sunset got the Rainbow Bitchslap of Harmony from Team Fakepony, she was forced to face the reality of what she had become and what she had done, and was understandably ashamed. Twi had held up a mirror to her new life, and she saw what she had become due to her ambition. If she had been inherently a bad person, I can see that she wouldn't have really felt that way, but I think she just let her own ambition blind her. As Fluttershy would say, she wasn't a bad pony, she just made a bad decision.

That movie was hella rushed. Heck, the entirety of Rainbow Rocks is pretty much them trying to salvage it and get something out of it

Tbf I don’t blame Sunset for making the decisions that she did. I bet I would have honestly turned out the same way if I was Celestia’a pupil.