Regret

"I don't know how I got here," Selena replied, keeping her voice even. "And I don't know where the old Selena went. It's all... Confusing."

It wasn't a lie. She genuinely had no idea how her transmigration into Selena's body had occurred, nor did she know where the original villainess had gone. Perhaps the cat would accept her vagueness.

Selena kept the information about this world being just a story, a figment of some author's imagination to herself. 

The feline's golden eyes narrowed, studying her intently. After a moment, it nodded, its expression unreadable. "Fair enough," it said. "You're not her, but you bear her body. You've inherited her burdens, whether you like it or not. I suppose it's only natural you'd have questions for me."

Selena exhaled quietly, relieved. "Then let's start with this: why dark magic? Why would she risk using it when it's so hated in this world?"