Misaka 10031 (ミサカ10031号 Misaka Ichiman Sanjūichi-gō?) is a Sister, a clone of Misaka Mikoto, that appears in both Toaru Majutsu no Index and Toaru Kagaku no Railgun. Originally having a small role in Toaru Majutsu no Index, her character was later expanded in Toaru Kagaku no Railgun. She is the 10031st clone to be produced and killed by Accelerator for the Level 6 Shift Project, and she is also the first clone Kamijou Touma meets.