Kumi Crystal is Derek's sister. She was formerly Jaxen and Jade's daughter but she had to move in with Derek's family due to her getting grounded. Her full name was formerly Kumi Vexy Ross but since she was living with Derek's family, her full name is now Kumi Denise Crystal (her middle name had to match her mom's name). Her brother Derek does a lot of stuff to anger her and get himself in trouble. She is a fan of MGM related stuff.