Demon Flowers(2003)

Kuruizaki no Hana

The gods of Japan have been eaten by Oni*(Oni are devil-like demons). The Oni who now hold our lives in the palms of their hands have been searching for the "Out-of-season Flowers" children resulting from the union of Gods and humans. In the midst of this, an Oni called Ushitoru had a fateful meeting with one such child named Masato. After saving his life, Ushitoru steals Masato from his family and takes him away... Now 11 years have passed. With the addition of a young human girl called Nao, the three of them are living life kind of like a family. The most important meeting in their lives-Ushitoru, Masato and Nao have ties to each other stronger than anyone's. (Source: ShoujoMagic)