Fujitsuka Yuki manga
Deimos was once a handsome god. He loved a beautiful goddess who returns his sentiments. The problem, well, she is his sister. For their crime against nature they were struck down out of Olympus. The brother is now a demon and the sister a rotting corpse at the bottom of the ocean. Deimos must choose between his sister and her living human incarnation. His sister is jealous. The girl is horrified and unsure of just what to make of her situation.
A wedding ruined by the suicide of a woman rumored to be a witch... Eiichi's affair ends in disaster as his lover hangs herself during his wedding to another woman. To the horror of the wedding guests, the dead woman gives birth to a girl. Eiichi and his new wife are forced to raise a child they don't want and don't care for. They name her Tsumiko (Great Shame). Now as a teenager Tsumiko resembles her dead mother more every day. She must compete with a younger sister, Megumi, who is everything she is not. As tensions rise at home and at school, Tusmiko will do everything she can to make her life better...