Comment by Choco on Kaya-chan isn't scary - Chapter 45

@Choco This curse requires an actual spell and a process to make, had Mirai never found the book that her aunt left for her, Kaya would have just been born a normal girl regardless of any grudge she held for the family. So by pushing her out they were intentionally trying to make the curse die, but because of her aunt she ended up doing it anyway.