ImaginationOfMine
Melanthe Cassiopeia Black Avery, daughter of death eater Regulus A. Black and seer Cassandra Avery, is forced to transfer back to Hogwarts for her fifth year after her twin brother and heir to the House of Black is found dead. His death leaves her trying to manage her new title, her power of premonition, and her life back in the same school as Fred Weasley.
"When Regulus died, there was not a glint of sadness in her grandmother's eyes. She was furious, another son had failed her. So, from that moment on, her grandchildren became her redemption.
So, with a dead father and an imprisoned mother, the Black twins were given to their grandparents, Orion and Walburga Black. It was the worst possible outcome of his death. They were the only option. Their Mother had been taken to Azkaban after being found guilty of murder shortly after their birth.
Morticia Cassandra Avery was driven mad by her visions. A Seer.
They were twins born into the burden of their fathers name, born with the burden of their mother's ability. Or so the prophecy said."