Inherited Vampire-Like Disease

Sapphire Grey Potter-McKinnon, is strange, shall we say. If her weird name and famous cousin (kind of) weren't enough, she's also a metamorphmagus and has a hereditary condition that gives her certain traits similar to those of a vampire. She just wants a normal life, but she just seems to attract trouble. Eventual Draco/OC. Slight Harry/Luna later. I'm not very good at summaries.