Her and her companions first appear friendly but later turns hostile in the main library of the White-Gold Tower.
"Sister Arminus assures us you're to play a vital role, today. Of course, she also said that we have no idea how lucky we are we haven't been whisked into the cosmic beyond. And then she laughed about it."
Is Sister Aminus sane? "You'd better hope she is. You're the one who agreed to help her."