Lilith Miyazuki, also known as Risu Miyazuki, attends Reien Girls' Academy with Azaka Kokutou, Seo Shizune, and Fujino Asagami. Her life revolves around the suicide of her close friend, Yuuko Andou, one victim in a series of unexplained student deaths at the academy. Before Yuuko's death, bound by a shared desire to "run away from the future," the two girls made a suicide pact. However, following a bitter argument where Lilith spoke harshly to Yuuko, Yuuko alone jumped from the Fujou building, influenced by Kirie Fujou's supernatural manipulation.

Consumed by profound grief and guilt, Lilith blames herself for the outcome, convinced her cruel words and failure to uphold their pact caused Yuuko's death. This trauma fuels ongoing suicidal thoughts; she contemplates cutting her wrists or jumping from a bridge. Haunted by unresolved anguish and self-recrimination, Lilith frequently visits the site of Yuuko's death to leave flowers.

A turning point arrives near a bridge where Lilith considers ending her life. She encounters Fujino Asagami, a blind classmate using a white cane. Fujino intervenes, employing a mix of intimidating tactics—like bending the bridge's metal structure—and empathetic dialogue. Sharing her own regrets, Fujino stresses the value of life and the potential for renewal each new day offers. This encounter shifts Lilith's perspective, pulling her back from self-destruction.

Later, during New Year 1999, Lilith visits Yuuko's grave, indicating a sense of closure and acceptance as she moves forward, having processed her grief and guilt. She possesses reddish-brown hair and red eyes.