Elizabeth Malfoy, Dracos younger sister in Ginnys year, is sorted into Gryffindor and makes friends with Ginny, Luna, Hermione, Harry, and eventually, Ron. She helps Ginny with Tom Riddles diary, boy trouble, and goes through all 7 years at Hogwarts being looked at differently, and stays strong through family... problems you could say. (Sorry about slow plot progression and if I mess up the order of events or something like that. Enjoy!)