Iron and Sapphires

HPTMR. After what he did to his brother when he was ten years old, Harry has devoted himself to atoning for it and to doing whatever he can for his younger sister, Amara. When she asks him to steal an artifact for her from the powerful Lord Gaunt, Harry agrees. He doesn't know what's waiting for him, or how thoroughly it will end his world. Darkfic, fourshot.