Kuroko Shirai is a Level 4 esper enrolled at Tokiwadai Middle School and a dedicated member of Judgment, tasked with maintaining peace in Academy City. Her Teleport ability allows instantaneous movement of herself or touched objects within an 81.5-meter radius, limited to 130.7 kilograms. This power demands intense concentration for spatial calculations and falters if her focus breaks. Before Tokiwadai, she could only teleport objects or others, mastering self-teleportation after enrollment. For Judgment duties, she arms herself with metal darts in thigh holsters, teleporting them to immobilize targets. Her family runs a major convenience store chain. She joined Judgment a year before entering Tokiwadai, where her first major case involved apprehending a bank robber with Equal Speed ability; she sustained injuries but was aided by a lightning strike. During this time, Sha Danshan, leader of the school's top clique, covertly stole one of Kuroko's hairpins to replicate her teleportation. At Tokiwadai, she developed an intensely obsessive romantic fixation on her senior and roommate, Misaka Mikoto, persistently calling her "Onee-sama." Kuroko's frequent attempts at physical intimacy provoke electric shocks from Mikoto. Despite this, her devotion is genuine, driving her to endure severe harm protecting Mikoto, like during the Tree Diagram Remnant incident. She exhibits deep possessiveness and jealousy towards others close to Mikoto, particularly Toma Kamijou. Kuroko displays a dual personality: playful and melodramatic personally, yet disciplined and resolute in Judgment duties. She strictly adheres to protocols, often rebuking civilians like Mikoto for intervening dangerously. Raised in Academy City's advanced environment, she remains unfamiliar with traditional Japanese customs outside, such as the "love umbrella" tradition. She shows skepticism towards unscientific phenomena, dismissing urban legends like Gemstones and initially rejecting Toma Kamijou's power-negating ability despite witnessing it. Her speech features the distinctive auxiliary phrase "desu no." During the Sisters Arc, she confronted Toma Kamijou after finding him with Mikoto, later aiding him by hiding him from dorm supervisors. In the Kazakiri Hyouka Arc, she attempted to apprehend magician Sherry Cromwell but was overpowered by a golem until Mikoto intervened; she later aided civilian evacuations. The Tree Diagram Remnant Arc proved pivotal. Tasked with recovering the Tree Diagram's remnants, she clashed with Musujime Awaki, a more experienced Level 4 teleporter. Awaki teleported objects into Kuroko's body and shot her. Critically injured, Kuroko psychologically taunted Awaki, exploiting her trauma and causing her to lose composure. Rescued by Mikoto and Toma, Kuroko reflected on her perceived weakness, resolving to become stronger to support Mikoto without burdening her. This left her temporarily wheelchair-bound during the Daihasei Festival, where she witnessed Mikoto aiding Toma, renewing her hostility toward him. Later, in the Academy City Invasion Arc, she handled office duties while monitoring citywide disturbances. She participated in security for the Interceptor Show during the Document of Constantine Arc. Her commitment extended into Genesis Testament, collaborating with Anti-Skill during Operation Handcuffs to apprehend dark side operatives. She later teamed with Toma Kamijou, Alice Anotherbible, and Yōen Hanatsuyu to halt Frillsand #G's rampage. Kuroko maintains a close working relationship with her Judgment partner, Uiharu Kazari, though her blunt opinions sometimes strain it. She shows unexpected kindness toward children, adopting a nurturing "big-sister" role. Her resilience is notable, recovering rapidly from severe injuries including gunshot wounds, dislocations, and repeated electric shocks.