Juliet Lupin is Moony's twin sister. She gets along great with James, and Peter, but one of the Marauders she can't stand to be around. Sirius Black has had a crush on Juliet since second year, but, seeing as how he's a flirt, and never takes anything seriously (Pun intended), she has always despised him. Then again, maybe things will go differently when they start their fifth year.