The Lady of Slytherin-Dark Beginnings

Lillith Potter, The-Girl-Who-Lived, appears before Severus Snape bleeding and broken at the age of six. Determined to protect his dead friends daughter from sharing her mothers fate he raises her to be brutally pragmatic, viciously opportunistic, and violently protective of those she loves with the help of the Black Sisters. Dad!Snape, Mentor!Bellatrix, DarkFem!Harry, Third Year