Sirius Black and his twin sister, Ylva Black are finally heading to Hogwarts for their first year. The twins are inseparable, and are attached at the hip, probably as a way to always feel strong. Both like pranks, but Ylva has a keen interest in reading that catches the one and only Remus Lupin's eye. See how Sirius and Ylva make their way through Hogwarts, hanging onto only a thread by their parents, in Book One of the Chronicles of Ylva Black.