A magical beast that has taken the appearance of a human female. In her first appearance she has long white hair and green eyes and looks like a woman in her late twenties. She uses her immense beauty to attract men whom she then lures into the forest, and after draining their magic, kills them and feeds upon their flesh. In this form she was so powerful that it took ten of the most powerful mages to try and eliminate her.
After her encounter with the Eugene and the other nine powerful mages her magic becomes sealed away and she subsequently turns into a human baby. Though many of the mages insist they need kill her whilst she is a weak infant Eugene intervenes, stating that killing a helpless child would make them no better than the beasts they battle against. Eugene agrees to raise her as he believes she might be a useful asset in the fight against the beasts. Eugene vowed to teach her how to use her immense magical power to help people instead of harming them.
Time skips forward seven years and Ayva now has the appearance of an eight year old human girl with the same beautiful green eyes but with black hair instead her original white hair. She is a very shy and timid girl, choosing to only speak with Eugene and when it is absolutely necessary and though she may be small she has quickly become adept at the magic Eugene had taught her. She is usually very calm and only loses her temper when seriously tested.
When her power becomes unsealed her power rapidly increases and she sprouts ethereal fox ears and tail. She also has a very powerful aura, appearing as a purple energy flowing around her.