Olivia is a Champion officer who is found locked in a cage inside the bunker near the Eagle's Nest teleporter in Orobas Fjords (where you fight Black Ring members Lady Kara and Lord John). She is the captain of the platoon that was stationed there until the Black Ring arrived and slaughtered them all, under the orders of Damian. Olivia's life was spared so that she could serve in what she describes as a "perverse ritual." Mindreading her reveals that she suffers from nightmares since being incarcerated, but results in no reward.
The key to her cage is on the beach directly below the bunker (near the large rib cage of bones). It can be found without doing so, but mindreading Beird upstairs then questioning him reveals that he threw the key out the window. If rescued, Olivia rewards you with the key to a locked chest (upstairs near the levers) before she departs for Aleroth.