Leona is Akira's biological sister and the obsessive focus of his unattainable desire. In his perception, she initially embodies perfection and commands his exclusive emotional attention. This fixation originates in childhood, where Leona imposed her influence, compelling Akira to dress as a girl to mirror her appearance and satisfy her narcissism. Her manipulation enforced the belief that his identity, particularly his name, belonged solely to her, establishing psychological control and emotional ownership.

Her possessiveness emerges violently when Akira forms a relationship with Kaname. Leona reacts with hostility, physically assaulting Kaname while making derogatory remarks about her social status and worth, revealing vindictiveness and a sense of superiority. This confrontation exposes the transactional nature of Leona's affection; she rejects Akira when his devotion wavers, demonstrating conditional and self-serving familial bonds. Her declaration that Akira is "no longer needed" confirms her primary interest is maintaining control.

The narrative reveals Leona subjected Akira to sustained psychological and physical abuse during their upbringing, fostering his emotional detachment and destructive behavior. Her fixation on him is interpreted as a projection of self-love, valuing only aspects reflecting her own image. This positions her as the antithesis to Kaname's unconditional acceptance.

Leona's exclusive privilege of using Akira's first name symbolizes her imposed dominance, a practice he initially reserves only for her until his emotional shift toward Kaname. Her absence in the resolution signifies Akira's liberation from her influence, aligning with the thematic conclusion that her perceived perfection masked selfishness and cruelty. Her role serves as the catalyst for Akira's internal conflict and psychological transformation.