Custodes Perdidit ex Memorias

Harry Potter has chosen to follow Voldemort and the wizarding world is falling into darkness. But this story isn't about him; when one light extinguishes another can be born and a would-be Death Eater finds himself embroiled in an ancient mystery. Alongside outcasts, ex-enemies and old allies, will the Dragon choose light or darkness? Only time can tell (Dark!Harry AU)