Olivia is a mouse banker who works at the Mozzarella Mutual Bank. Her job is to collect a "cheese tax" from the general populace. She has shared almost no details about the actual bank itself, and refuses to elaborate on what exactly this "cheese tax" is, or its purpose. People being unable to pay this tax upsets her greatly. Gets VISCERALLY ANGRY when someone questions why her name is "Ratstein," despite being a mouse.