will illyria die?is she going to be fred again?what about her and her death?

I suggest reading Angel: After the Fall and finding out for yourself.

I don't know it Illyria will die but she can't revert back into Fred. Though she can change into her. According to what Illyria told Wesley, Fred's soul was destroyed in bring Illyria into being. It is sad, Fred was a great charactor