Berdasarkan lagu Vocaloid yang populer.
- Alternatif: 秘蜜 黒の誓い, Alluring Secret – Black Vow, Alluring Secret ~Black Vow~, Himitsu ~Kuro no Chikai~
- Tipe: Light Novel
- Bahasa Asli: Japanese
- Status: Completed
- Rilis: 2012
- Genre: Drama, Fantasy, Gender Bender, Romance, Supernatural, Tragedy