Olivia was once a young ymbryne in training before an unknown accident left her injured and unable to shift back into her human form. Despite being brought to Miss Wren, Olivia was unable to be helped and remains an owl residing in the menagerie. Her status is unknown after the wights raided the menagerie, however, as Addison didn't mention her among the fatalities she can be presumed alive. She was 11 when she turned and is now 21.
She is an ymbryne, which gives her the power to manipulate time and turn into a bird, specifically an owl.