I don't agree with Ivy reaction but I understand it, Chise to this point an amalgam of many things, naturally she was already special but now she has a curse of immortality extremely powerful and a dragon curse that do whatever, she still has a link with a "cursed"(?) magic fox pelt that allows her to turn in different animals and a link with a Fae.
Let's be honest she is a monster, but she is our little monster, and I don't think Ivy is a pure-blood monster by his reaction I think is some sort of condition.