Comments posted to our Dark Souls 3 Wiki
I was having trouble, but then I tried ferron greatsword. Dodge a fireball, do a full two handed alternate light attack combo, she can't do a thing.
chest ahead.
She isn't immune to toxic, but she has very high resistance to it, and it's not at all worth the struggle.

If you're having trouble, use a whip, as she dodges poorly against them.
annoying ***** is what she is..