The only person who was not sacrificed was her husband who was not related by blood to Ash.
All of her cousins who were sacrificed were female and they all varied in ages so she could transform into a variety of different forms but there was one major issue with that.
Some of them had very strong genes that made them take on similar traits and looks like Ash and her mother did.
Those on that side of the family had a close resemblance to Ash and that was a problem for her.
If they looked different than her then perhaps she may have been more likely to keep using their forms if she ever needed to do so.
If she used those forms then she would always end up taking on a form that closely resembled her original appearance.
Her true identity and her connection to those of her bloodline were things that should never be exposed.
Ash had no other choice but to stop using those forms unless she had no other option available.
