Mio Naruse (成瀬 澪, Naruse Mio) is the main female protagonist of the series. She is the daughter of the previous Demon Lord, Wilbert and a human named Ashe thus making her a humanoid demon, as well as the niece of Sapphire. After the "death" of her father, Mio inherited his power and was raised in the Human World as the daughter of two unnamed demons as a human. Though after the death of her adoptive parents, she was later saved by Maria who revealed the truth about her lineage.