Beyond The Shadows

just a fan fic, pretty good anime so why not?
for those who haven't read or watched The Betrayal Knows My Name, General Class Opast= higher ranking duras or demon. Duras= Daemons Zweilt= Daemon hunters possessing powerful abilities. Familiar= an animal companion who fights on the Opast's side.
While in General Opast Ashley's little fun house, as Hotsuma and Yuki search for their friend Shusei, the find a room in which they peer inside hoping Shusei is in there, but instead of Shusei, they find a woman trapped in crystal, she seems distressed and Yuki convinces Hotsuma to free her, once they do, the woman offers to help them find their friend, but the woman soon reveals suspicious traits, one of them being her knowing they are Zweilt. Who and what is this woman? Can the Zweilt trust her? and What else does the woman know, or rather...Whom?