This is the second time I read this manga, and believe it or not, I was confused at where thit Hikaru just knew that the ghost was her mother, perhaps I was distracted while reading, but this translation helped me a bit in understanding this.
So, my guess is that the ghost in her afterlife, was raped and pregnant at the age of 12, which makes Chintauro an some kind of unwanted child that perhaps maybe someone adopted. Their parents may not have treated her well, and that may be the reason she wanted freedom, and that she was broken before contacting with Hikaru (and the reason she fell in love with him is 'cause he was the only one who helped her along the way).
Can't believe i'm working up this much on a manga focused on paizuri