Shirai Kuroko

is a character in both Toaru Majutsu no Index and Toaru Kagaku no Railgun. She is voiced by Satomi Arai.

Misaka's kouhai in Tokiwadai Middle School and a protagonist in Toaru Kagaku no Railgun and main character in the eighth volume of the Toaru Majutsu no Index light novels. A Level 4 psychic, she is a member of, a special public committee group whose duty is to maintain peace and order in Academy City. She has an unhealthy obsession with Misaka, who she calls "Onee-sama" (big sister); she is in the constant lookout for a chance to get physically intimate with Misaka (and getting called a pervert in the process), and tends to get jealous if someone else gets her attention; this unfortunately happens to be Touma since he has caught the attention of Misaka for various reasons. Her powers are instant teleportation (and she is called a because of this), which allows her to teleport herself and anything in her possession. In volume 8 it states the limits of her powers to be total weight of the items being teleported not exceeding 130.7 kilograms, and to a limit of distance to a radius of 81.5 meters from her. One disadvantage of her power is that she has to concentrate on where she, the object(s), and/or person she holds would be teleported to, while working out the spacial co-ordinates of jumping between 3-dimensional and 11-dimensional space, so any disturbance in her concentration will make her powers useless, as demonstrated in her fight against Sherry Cromwell.