A character from the anime/manga series Toaru Kagaku No Railgun. She is a classmate of Uiharu Kazari. Ruiko is said to have no potential for esper powers, although she was temporarily able to wield Aero Hand, a similar ability to Kongou Mitsuko, through the use of Level Upper.
Ruiko's obsession with the occult and urban legends, while often harmless and only a prompt to get told off by Kazari for being too gullible, sometimes leads to interesting or potentially dangerous involvements - such as being kidnapped and unwittingly rescued by Frenda Seivelun, with whom she developed a quick friendship that came to an uncertain end on her side due to Frenda's brutal death.
