Yūma Tokoyogi, a childhood friend of Kojou and Nagisa Akatsuki, first met them while helping Kojou retrieve Nagisa's hat from a cliff edge. Her origin reveals she is not human but a clone created through parthenogenesis by Aya Tokoyogi, programmed with the singular objective of breaking the Demon District Prison Barrier's seal to free her mother. This purpose drives her existence, leading her to orchestrate a body swap with Kojou by kissing him, exploiting his status as the Fourth Progenitor to access the magic required for the barrier's release. Her motivation stems from a desperate search for meaning, clinging to her memory of meeting Kojou as her only perceived possession. Physically, she has short brown hair with long bangs covering most of her forehead and distinctive purple eyes, often dressed in a tomboyish style. Her personality blends a caring, playful demeanor with underlying independence, though her actions are fueled by an internal struggle to justify her existence. Despite her inherent kindness, she proceeds with freeing the criminal Aya Tokoyogi, fearing the loss of her raison d'être if she abandons her mission. Her abilities include body switching through direct contact, teleportation, and command over Le Bleu—a knight-like guardian spirit in blue armor capable of distorting space-time. During the prison barrier incident, she frees Aya only to face immediate betrayal; Aya dismisses her as a disposable "doll," stabs her, and uses her as a decoy in an assassination attempt against Natsuki Minamiya. Aya then steals Le Bleu by forming a blood bond. Following this, Yūma becomes Kojou's fourth blood partner, solidifying her ties to his group. After the confrontation, Yūma integrates into Kojou's circle, transitioning from antagonist to ally. Her development concludes with her future marriage to Kojou within the series' narrative timeline.