In the seriesEdit
In Storm Front, Harry Dresden goes to ask her questions about Jennifer Stanton, who was murdered, and Bianca St. Claire immediately attacks Dresden thinking he's her killer. During the tussle, part of her human mask tears away revealing a hideous bat-like creature underneath. Dresden swears by his powers that he did not kill Jennifer. She gives Dresden the name of Jennifer's friend, Linda Randall. Dresden sees in her eyes that she will not forgive him for unmasking her. She vows to make Dresden pay. — Her assistant Rachel enters as Dresden leaves, he witnesses St. Claire devour her. 
In Grave Peril, Bianca St. Claire hatches a plan that would undo Amoracchius, kill Harry Dresden, and instigate a war between the White Council and the Red Court. She infects Susan Rodriguez with the vampire toxin, then manipulates Dresden into fighting the vampires to get her back, thus starting The War. Near the end, St. Claire and the majority of her coven are killed by the spirits of those she killed, led by Rachel's coven.