An old AU that had been mentioned before (I think) has reached its 140th chapter, with the beginning of Book Seven. Prince of the Dark Kingdom is an AU where a sane Voldemort is a follower of the old druidic gods, and conquered Magical Britain ten years ago, imposing not concentration camps but strict segregation from the muggles, forcible integration and confiscation/obliation of muggleborn chidren. The Potters fled Britain to live as muggles in Europe, but an accident leaves Harry orphaned and he is sent to the Dursleys by muggle social services, where he gets picked up among other muggleborns. He soon catches the eye of the Dark Lord, who despite the prophecy decides to make him into his disciple and putative heir. The setting adds druidic magic and old gods, meddling Fae, and Stalin!Voldemort.
The other one is Firebird's Son by Darth Marrs. Here, there are a few biological differences between magicals and muggles, which enforce a stricter separation, and more importantly a matriarchal polygamic society, where the wizards may be paid some lip service but the real power lies in the witches that bound them. The kind of society that would would not keep Tom Riddle from becoming a monster, but make him even worse... and it might deserve him. There is plenty of evil to go around everywhere in this AU, and a more naive Harry is off the deep end. Fair warning: like most from this author, this story is meant to be disturbing (sex, rape, and power politics among both kids and adults), and the latest chapter - 15 - while staying within FFnet regs should be considered NSFW.
The other one is Firebird's Son by Darth Marrs. Here, there are a few biological differences between magicals and muggles, which enforce a stricter separation, and more importantly a matriarchal polygamic society, where the wizards may be paid some lip service but the real power lies in the witches that bound them. The kind of society that would would not keep Tom Riddle from becoming a monster, but make him even worse... and it might deserve him. There is plenty of evil to go around everywhere in this AU, and a more naive Harry is off the deep end. Fair warning: like most from this author, this story is meant to be disturbing (sex, rape, and power politics among both kids and adults), and the latest chapter - 15 - while staying within FFnet regs should be considered NSFW.