Accelerator is the most powerful esper in Academy City, holding the top Level 5 rank. His pale skin, white hair, and red eyes result from his ability blocking ultraviolet rays and reducing melanin. An androgynous appearance stems from his power limiting external influences, causing hormonal imbalance. His ability, Vector Transformation, grants control over vectors in both direction and magnitude. It functions passively and actively. The passive form, Redirection, subconsciously reverses any harmful vectors approaching him, deflecting bullets, heat, electricity, and radiation. This defense can be subverted by vectors pulling away before contact or attacks operating on unknown laws. Active Vector Control requires conscious calculation, enabling manipulation of phenomena like earthquakes, wind, plasma, ground, sound, and object acceleration. It can also influence human bio-electrical signals to alter memories or personalities, though such complex applications demand intense focus and leave him vulnerable. Isolated in childhood due to uncontrollable power that harmed others, an incident where he injured children led Academy City to intercede. Placed in special classes, often alone, he was later trained by Kihara Amata, who shaped his personality. Accelerator joined the Level 6 Shift experiment, which involved killing 20,000 clones of Misaka Mikoto. His perceived motive was a quest for ultimate power, but his true aim was to become so strong that no one would challenge him, allowing him to form friendships without fear of harming others or being threatened—a naive desire born from loneliness. After killing over 10,000 clones, he was defeated by Kamijou Touma, who made him recognize the clones as living beings. This triggered profound guilt. Following the experiment’s end, he encountered Last Order, the final Misaka clone and control tower of the Misaka Network. Though initially reluctant, he developed a protective bond with her. A headshot severely injured Accelerator, reducing his computational capacity to less than half. He now depends on an external electrode for computation, mobility, and communication, using a crutch for support. This led him to protect Last Order and confront threats from Academy City’s dark side, such as the organization Disciplinary Action (DA), which sought to exploit her. Conflicts with DA members and encounters with Esther Rosenthal further defined his role as a guardian. His abilities evolved to analyze and manipulate vectors based on unknown laws, including those involving magic, though with physical repercussions. He participated in events like the Endymion incident, helping neutralize threats to the city and demonstrating a shift toward protection despite his claims of indifference. His journey spans the main series, spin-offs such as *A Certain Scientific Accelerator*, and films, where he faces adversaries like necromancers and organizational conspiracies while atoning for past actions. He transitioned from a villainous figure to a complex protector focused on safeguarding Last Order and opposing Academy City’s corruption.