Saten Ruiko is a fictional character from the light novel and anime series A Certain Scientific Railgun, which is part of the larger A Certain Magical Index universe. She is a student at Academy City and is known for her cheerful personality and strong sense of friendship. Saten is classified as a Level 0 esper, meaning she has no supernatural abilities, but she often finds herself involved in various adventures alongside her friends. Saten is characterized by her short, dark hair and casual clothing style. She is a member of the Judgment organization, which helps maintain order in Academy City. Despite her lack of powers, Saten's determination and resourcefulness make her a beloved character among fans of the series.