Elise manifests as the physical form of Ōgai Mori's ability, Vita Sexualis. Her very being reflects Mori's shifting moods and desires, dictating her behavior and appearance. Active since the Great War, she first served Mori with robotic obedience, addressing him as "master" and lacking her later vitality. Her appearance remains that of a young girl, per Mori's preference: pale skin, bright blue eyes, and long blonde hair styled with blunt bangs and waist-length ringlets. She typically wears a red dress with a white hem, black and grey stockings, and red Mary Jane shoes, often accessorized with a large red bow. Her eyes become reptilian when her ability activates. In combat, she wears a frilly pink nurse uniform with a black corset, white socks, and black Mary Jane shoes, wielding a giant syringe reflective of Mori's surgical background. After the Great War, Mori reshaped her personality to mimic a young Akiko Yosano following Yosano's breakdown, transforming Elise into a replacement figure. This resulted in her current temperament: a spoiled, defiant child prone to tantrums when displeased. She exhibits sadistic tendencies, enjoys inconveniencing Mori, and shows little concern for Port Mafia members despite often playing with them. She frequently insults Mori, calling him "Rintarō," "Mr. Midlife Crisis," "Stupid Rintarō," "Idiot," or "Cheapskate," reflecting her resentment toward subservience. Her interests include drawing, sweets, and manipulating Port Mafia members into activities like shopping or hairstyling. However, during combat, her personality vanishes entirely; she becomes emotionless, unblinking, and vicious, reverting to a purely instrumental extension of Mori's will. Fleeting hints of fondness for Mori may surface after defeats, such as against Fukuzawa. Elise functions as both Mori's companion and combat asset. He dotes on her excessively, buying dresses and offering sweets to persuade her, though she often rejects his requests. She accompanies him publicly, sometimes posing as his daughter. Mori prioritizes her safety, as seen when he remained in Lucy Montgomery's dimension fearing her capture. Elise observes many Port Mafia operations and Mori's schemes without intervention. In combat, she displays superhuman strength, high-speed flight, and regenerative capabilities; if "defeated," she disappears but can be resummoned by Mori, though any cooldown period is unspecified. Her abilities allow her to save Mori instantaneously in dire situations without explicit commands. Her name and dynamic with Mori reference his short story "The Dancing Girl," exploring obsessive affection. She is one of two abilities shown to speak during the Dead Apple incident. Official illustrations depict her in a former military uniform during the Great War, holding a doll while her shadow resembles Yosano's form, reinforcing the personality shift. Her love of sweets may originate from Yosano’s pre-war job at a candy store. In alternate universes, Elise appears as a grown woman.