One of the protagonists of "A Certain Magical Index." He serves as the sole protagonist in the spin-off "A Certain Scientific Accelerator." The strongest esper, reigning as the Rank 1 of the only seven Level 5s in Academy City. He possessed calculation abilities far beyond that of an ordinary person, though later... Incidentally, "Accelerator" is his ability name; his real name is currently unknown (according to him, it is a "commonplace name" with a two-character surname and a three-character given name). According to Kounagi, it is a surprisingly cute name. In the crossover spin-off with Cyber Troopers Virtual-On, "A Certain Magical Virtual-On," he is a Specineff user. He has an androgynous, pale appearance with white hair and red eyes. This is because his ability reflects all ultraviolet rays, preventing him from tanning at all. In the original novels, the narration from Amata Kihara's perspective describes him as having "well-defined features." According to setting materials, his height is 168cm. As he lived relying entirely on his ability, his body is very slender. While he is generally treated as male in the series and voiced by a male actor, his gender—much like his name—has never been explicitly stated. Therefore, third-person pronouns and titles in the narration avoid gendered terms like "he" or "she" as much as possible. His most distinct preference is his obsession with canned coffee. When he takes a liking to a specific brand, he will repeatedly buy and drink the same coffee until he grows tired of it. Regarding food, he seems to prefer meat dishes. When Awaki Musujime, who was eating a salad, expressed exasperation at his nutritionally unbalanced lunch of spicy fried chicken and canned coffee, he remained nonchalant, saying, "Isn't it a happy way to go, dying while eating only what you like?" In the anime bonus feature "Go Forth, Accelerator! The Hectic Advance," he calmly finished a bowl of abura soba at a ramen shop, and for some reason, also finished a beef bowl found at the same shop (he himself pointed out that since it's a ramen shop known for tonkotsu and chashu, it should usually be a pork bowl), though the amount seemed to be a bit much even for him. The eye-catches are also filled with food. His ability is activated by contact with a thin, protective-film-like layer surrounding his body. He can perceive and transform the vectors of things like momentum, heat, and electricity just by touching them. It is usually set to "Reflection," reflecting every physical phenomenon that touches him subconsciously. He can also perceive and transform things that cannot be recognized by the five senses, such as low frequencies and radiation. Following the laws of physics, he subconsciously constructs a filter for harmful and harmless substances; things necessary for life (like minimum oxygen and gravity) are set as "accepted vectors," while "all other vectors" are set to be reflected. He can also reflect harmful sounds and other phenomena by manually reconfiguring his settings.