From my knowledge of they Japanese mythology, the haunt looked like the ikiryo, the living ghost, aka part of the person's soul haunting the others. That makes the damage transfer make 100% sense....Wait, did-
Did Kaya transfer the damage she inflicted to the curse (one I'm sure the mother had no idea she was casting) back to the caster?
That's...kinda scary, right? That she can remotely harm you for things you might not even be aware were your fault...?
Sure, it happened to a bad person this time.
This time.