emzyweasley
Sarah Slytherin is friends with Draco and they rest of Slytherin and she is just as bad. She bullys everyone that isn't in Slytherin but she's even more mean to Harry Potter and his friends. One day (in 3rd year), as she's walking round Hogwarts, she starts singing, not realising that people were listening to her. They convince her into join their band and she leaves Hogwarts, only to come back in her 5th year, where people realise she's changed.