Leone Olfa is a holy knight-in-training and the younger sister of Leon Olfa, a former holy knight who betrayed their order. His actions resulted in the death of their parents and left Leone an outcast, shunned by citizens and tormented by schoolmates. This suffering forced her to abandon her love for her brother, replacing it with a deep-seated hatred.

She has long purple hair, typically tied into pigtails with black ribbons, and wears the standard female uniform of the Royal Knight Academy.

Kindhearted and hardworking by nature, Leone endured great pain due to her brother's betrayal. Her driving purpose is to become a holy knight, arrest Leon, and make him answer for his crimes and their parents' deaths. She is fiercely determined in this goal, vowing never to forgive him. She exhibits discomfort in response to inappropriate behavior, such as invasions of her personal space or the use of unwelcome nicknames.

In combat, Leone demonstrates immense physical strength and speed, wielding a large claymore with expert skill. Her abilities include proficient swordsmanship and Size Magic, which allows her to manipulate the size of her weapon. She is recognized as the second strongest first-year student at the academy, behind only Inglis Eucus.

Leone shares a strong friendship with Inglis Eucus and Rafinha Bilford, who stood by her when others turned away. She rooms with Liselotte Arcia, who initially distrusted her due to Leon’s betrayal but later apologized and accepted her. Leone’s most defining relationship remains with her brother, Leon, whom she confronts on multiple occasions, each time reiterating her hatred and unwavering resolve to see him captured.

During one patrol with Liselotte Arcia, Leone confronts Leon, revealing the truth of their parents' fate and engaging him in combat. Despite his attempts to reason with her, she holds firm in her opposition.