Mahiru Hiragi

The black demon residing in Mahiru's night. A beautiful girl with gray hair, wearing the uniform of First Shibuya High School.

Her true identity is that of Shinoa's older sister and Guren's former lover, a genius with both beauty and brains who completed the demon-possessed equipment and saved the world. Like her half-brother Kureto, she held the position of a candidate for the next head of the Hiiragi family, but eight years ago, she betrayed the Hiiragi family and was officially reported to have been killed by Guren. Although Shinoa describes her as untrustworthy, she has a sisterly nature, sacrificing herself to protect her younger sister.

She became acquainted with Yuuichirou when he was confined in the Hyakuya Sect's prison after his mother committed self-immolation. She spoke to the despairing Yuuichirou about "living," affirming his existence. Although Yuuichirou's memories of that time were erased, he vaguely retained them and regained those memories upon their reunion, feeling relieved when he heard his reason for living.

Before the world collapsed, she attempted to contact Krul using "Yuu," "Mikaela," and "Ashera" as bargaining chips, and succeeded in becoming a vampire with Krul's blood, maintaining a cooperative relationship with her thereafter.