Olivia begins as the protagonist in the original otome game narrative within the Holfort Kingdom. A commoner enrolled through a special scholarship, she faces consistent bullying and social isolation from noble students due to her lower-class status. This background fuels significant self-doubt and feelings of inadequacy during her early academy life.

Physically, she possesses light brown hair styled in a medium-length bob cut and greenish-blue eyes. She carries herself modestly and is described as beautiful, though not as strikingly noticeable as noble peers like Angelica Rapha Redgrave. Her personality centers on kindness, gentleness, and a strong aversion to gambling. She frequently experiences stress over the academy's luxurious environment and high costs, contrasting with her humble origins.

Her character development starts through friendship with Leon Fou Bartfort. They first connect after noble students tear up her royal tea party invitation; Leon consoles her and shares leftovers from his own gathering. Leon later facilitates her introduction to Angelica by funding a gift, leading to a critical meeting where Angelica permits Olivia to remain at the academy provided she maintains appropriate conduct. This interaction begins a complex bond among the three.

During a mandatory dungeon exploration class, Olivia partners with Leon. After monsters injure Leon, she demonstrates healing magic, revealing her aptitude for restorative abilities. Her academic prowess surfaces through self-study, where she identifies textbook errors surpassing most noble students. Despite this intellect, her lack of confidence resurfaces as she questions her worth beside Leon and Angelica, exacerbated by escalating bullying incidents that include threats against her family and destruction of her living quarters.

A pivotal transformation occurs during the Principality of Fanoss invasion. Olivia awakens latent magical abilities as the Saintess, generating a massive protective barrier around the academy's airship that deflects cannon fire and destroys enemy warships, saving hundreds of lives. This display stems from accumulated knowledge gained during Leon's overprotective periods and her newfound resolve to defend friends. The event shifts peer perceptions, reducing prior bullying and cementing her academy significance.

Her Saintess powers include force-field creation, light-based attacks, healing, statistics amplification, and negation of regenerative immortality. She exhibits reaction speeds sufficient to intercept cannon projectiles and range capabilities covering entire structures. These abilities necessitate training with three sacred artifacts, a quest Leon supports despite initial reluctance to share his meta-knowledge of the otome game's storyline.

Olivia's relationships evolve substantially. She develops romantic feelings for Leon, confessing directly and agreeing to a polyamorous engagement alongside Angelica. While trusting both partners, she displays intense jealousy in scenarios like the Alzer Republic arc, concealing anger behind threatening smiles when perceiving romantic rivals. Her dynamic with Angelica shifts from transactional guidance to genuine camaraderie and mutual protection against political schemes.

In later arcs, Olivia balances her scholar identity with her Saintess role. She pursues studies on magic theory while accepting responsibilities tied to her powers, such as confronting supernatural entities like ghosts. Her journey reflects continuous growth from a timid commoner to a confident individual who asserts her humanity against being treated as a passive "pet" or game character, including confronting Leon about his initial motivations stemming from viewing her as the game's heroine rather than an equal.

She concludes with sustained compassion and loyalty, adopting more forward and occasionally pushy behavior in expressing desires, particularly concerning Leon. She remains central to resolving conflicts involving the Holfort Kingdom's stability, utilizing her Saintess capabilities to neutralize existential threats.