A Black Ally

Thrown into Azkaban after losing his best friend and godson, Sirius Black doesn't have any reason left to live. That is until a tiny slip of a girl with his brother's face gets on her knees, begging him to come back into the house he left at 16. The House of Black is not dead yet and Arcturus will see it thrive again. AU. Neville BWL. Pureblood/Paganism culture.