The Supervillain Twins are a pair of identical 10-year-old twin sisters named Milly and Tilly, and they are known as 'Ruthless Rockstar' and 'Poisonous Princess' respectively. Milly's costume consists of a black long-sleeved full-body rubber jumpsuit with a skull and crossbones in the center, a pair of black swimming goggles, a pair of black rubber gloves, a pair of black boots, a black supervillain cape and a lot of piercings on her nose, eyebrows and ears. She has the power to play her electric guitar so loudly it can shatter glass. Tilly's costume consists of a green long-sleeved full-body rubber jumpsuit, a poison green princess dress, a pair of leafy green swimming goggles, a pair of forest green rubber gloves, a tiara with a skull and crossbones in the center, a dark green supervillain cape and a pair of green rubber boots. She has the power to poison her enemies by either touching them or sending out poisonous powder from her dress or hands. The twins have one major goal: to take over and rule the entire world.