Signa Riddle

Signa Nathalia Malfoy (née Riddle), the youngest and only child to Declan and Juniper Riddle (née Smith), was an Irish Half-Blood witch who attended Hogwarts School of Witchcraft and Wizardry from 1991-1998 and was sorted into Slytherin.

Signa was originally born into the Atchley family, by Delphini, but given to the Riddle's since Juniper was unable to have children. Delphini and her husband Cato's son, Salem, had always believed Signa was his hated cousin. Signa had the same beliefs.

Salem also went to Hogwarts a year before her, sorted into Slytherin as well. She immediately became friends with classmate Pansy Parkinson, and then began dating Draco Malfoy in their fourth year. Declan and Delphini gave up in 1995, forcing their kids to become Death Eaters, Draco the year after.

In her second year, when the Chamber of Secrets was open, many speculated that Signa or Salem was the Heir of Slytherin, considering their relation to Lord Voldemort.