Tanith Lee 
Darkness, I [EPUB ebook] 

Anna, white-haired and grey-eyed, is born into the luxurious and mysterious family of Scarabae, a family of inhuman age and consuming passions. As she matures, it becomes clear that she shares some of their blood, for at three she appears sixteen, and holds knowledge known only to her dead sister Ruth… Suddenly Anna, along with a score of other children, is kidnapped and carried away to the end of the earth, to the pyramid hidden in the Southern ice that is home to the terrible immortal named Cain.