QUICK BIO
Rei´s father betrayed his wife with Rei´s mother. Rei grew up at her mother´s place and after she had died, Rei´s father "adopted" her when she was ten. He had two other children, Fukiko and Takehiko, both older than Rei. Rei fell in love with her sister Fukiko. After finding out that her father had betrayed her mother, Fukiko wanted to kill Rei, pretending to love her back and to die with her. But fortunately Rei did not die.

SOURCE: Oniisama e