Quote Originally Posted by Archangel
From the last episode of the first season i'm also assuming his doll gained some extra abilities from being in ground zero that time.
I am offended you do not know Yin's name!

Surely her lack of appearance was the most disappointing part of the first episode, though it was offset a slight margin by Tanya's character design. It is very likely she has expanded abilities or personality, given how her observation spirit went from the little ghost it usually is to a manifestation of what I can only presume is her full astral form.