@Katy05 that's not why we're worried, because her plans are always stupid. It's more due to the fact she has a possession of hers, and she could use it for an even worse curse.
No wonder there was a warning in the description! This girl not only takes the villainess position VERY seriously, but we never get any "Aaaaah! I can't believe I said/did that! Why did I have to reincarnate in this role?!"
What an act! Laughing maniacally during a thunderstorm, cultivating venous butterflies and immunity, educating the little brother on her plans and punishing the little sister like it's literal child's place! She is the true villain of this story!