Man, a bitch from when she was young, and forever a bitch.
Killed her sister with a fucking lie, "regretted" it after it made very clear that the sacrifice was useless, not that she believed in it, just used it to kill someone she despised, and if it was truly her treasure she would have never selected her, so the ritual wasn't followed from the very start.
It finally came to her what she did after it was way too late, and she simply escaped the place, when she came of age she stopped talking about the murder she ordered, fearing real repercussions.
She made a vengeful ghost, that still loved her too much to finish the job, ignored it for decades, kept it hidden, and now that she is old and close to the grave can accept a sentence that woulnd't put her anywhere, even because when this manga was done the status of limitation on murder was 15 years.