Bio: Misaka is the third ranked Level 5 esper in Academy City, and is nicknamed the Railgun due to her signature move. To most people, she is considered a dream girl but in reality, she's a childish, short-tempered, prideful, and has an improper attitude with some slight tomboyish tendencies and insecurities. Despite of this, she is generally friendly and easygoing, moreover, she really care about people around her.
Bio: Misaka's Sister is a clone of Misaka Mikoto that ranked Level 2-3 esper. This clone is mass-produced about 20k individuals. Their DNA were gathered from Misaka's hair when she's still a kid. They're trained in the use of military standard weapons. The purpose of their mass-production is for the Level 6 Shift program – an experiment designed to make Accelerator, the strongest Level 5 in Academy City. After that experiment terminated, they began to live an ordinary life.