The daughter of businessman Tabigake Misaka and his wife Misuzu, Mikoto was discovered to be a Level 1 Electromaster at a young age. After enrolling in Academy City, Mikoto trained hard to become a Level 5 - the highest esper rating. Her powers allow her to generate and manipulate electricity which she uses to shock opponents and hack into computer systems as well as shoot metal projectiles at high speeds, earning her the nickname “Railgun.” She also has the nickname “Biri Biri” (“Bug Zapper” in the English dub of the anime) which was given to her by Kamijo Touma.
Mikasa attends Tokiwadai Middle School and despite her tomboyish appearance secretly loves cute things such as the popular frog character Gekota. In her spare time, she frequently heads out to Green Mart to read manga and enjoys playing the violin which she even teaches her friend Uiharu Kazari to play too.