Accelerator holds the highest Level 5 esper rank in Academy City, wielding the power "Vector Change" to manipulate vector quantities such as direction and magnitude. This manifests passively as automatic redirection of incoming threats like bullets or energy projectiles, and actively as control over environmental vectors including wind, ground, sound, and bio-electrical signals. Sustained use demands immense computational power, a limitation amplified after a severe injury. Physically, Accelerator displays an albino appearance—white hair, pale skin, and red eyes—caused by his power blocking ultraviolet radiation and reducing melanin production. Hormonal imbalances from his ability contribute to an androgynous physique. Following a head injury, he relies on an electrode for communication, computation assistance, and mobility support via a crutch. He typically wears black-and-white clothing and adopts a distinctive manic grin during intense combat. His background involves significant trauma. Uncontrollable powers harming others led to childhood isolation and specialized education under Academy City. Scientist Kihara Amata trained him, shaping his cynical worldview. Accelerator participated in the Level 6 Shift Project, requiring him to kill 20,000 clones of Misaka Mikoto to elevate his power. He initially believed this would deter challengers and prevent accidental harm, but his rationale twisted under the city's influence. The experiment halted after he killed clone 10,031 and was defeated by Kamijou Touma, forcing him to confront the clones' humanity. A pivotal shift occurred when Accelerator encountered Last Order, a central figure in the Misaka Network. After saving her from a virus attack, he dedicated himself to protecting her and the surviving clones as atonement. This protective drive extended to opposing threats like the Hound Dogs, Freshmen, and Coronzon. Though self-identifying as a villain, his actions increasingly focused on safeguarding innocents, including children like Fremea Seivelun. He formed limited trusts with individuals such as Kikyou Yoshikawa, Aiho Yomikawa, and Heaven Canceller. Post-injury, Accelerator's computational capacity reduced to less than half, restricting high-precision applications like memory alteration and imposing a 15-minute combat limit without external processing. He later developed transformative wings: black wings emerged during extreme emotion, enabling matter disintegration and flight; white wings appeared after interacting with magic, granting enhanced vector manipulation and resilience; platinum wings manifested during the Clonoth Arc with Qliphah Puzzle 545's support, correlating with multiversal-scale capabilities. Each form symbolized psychological or power shifts. As a reluctant leader, Accelerator eventually became Academy City's Board Chairman. In this role, he prioritized civilian safety during conflicts like World War III and organized operations against supernatural threats. He maintained a pragmatic moral code, refusing to harm bystanders even while confronting adversaries like Teitoku Kakine. His dynamic with Touma Kamijou remained complex—marked by rivalry, mutual respect, and occasional alliances against common foes. Accelerator envied Touma's non-lethal conflict resolution but accepted his own methods as necessary for protection.