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 is in love 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. During Volume 8 Kuroko faces off against Awaki Musujime who has a remnant of the Tree-Diagram and Kuroko faces off against her but Awaki proves to be the better teleporter. Awaki teleports a corkscrew into Kuroko's side, she teleports her spikes into her as well, and even shoots her with a gun. Kuroko returns the favor back at Awaki during their second encounter, but due to Kuroko running around all night with out rest she cannot teleport anymore so she resorts to psychological tactics against Awaki. Awaki's accuracy starts to fail and then she decides to teleport a 4.5 ton object onto Kuroko. Kuroko unable to do a thing gets saved by Touma who uses his imagine breaker to stop the teleport. Kuroko is then taken to the hospital. She is also seen in a wheel-chair during the School Festival.