Saten Ruiko (佐天 涙子Saten Ruiko) is a character from the Toaru Kagaku no Railgun sidestories. She is a Level 0 Academy Citystudent and is a classmate and close friend of Uiharu Kazari.
Saten Ruiko is a girl with blue eyes and long black hair with a small, white flower on the left side of her hair. She also prefers wearing medium-sized skirts instead of short ones.
She has an outgoing and friendly personality but is a little shameless as she sometimes flips Kazari's (and only her) skirt in public. At first she displayed apathy towards being a Level 0 but then became envious of the abilities of her friends as she was unable to fulfill her dreams as an esper, as such she used the Level Upper. Later on she grows to accept herself and becomes determined to develop her own abilities. Like her friend Kazari, she also has a deep sense of friendship, she was instrumental in helping Kazari and Kuroko make amends and made Mikoto realize that she has friends who she can count on. She's a huge fan of internet rumors and loves telling her friends about them.
She was born outside Academy City and when she was younger she decided that she wanted to go to Academy City to become an esper, she even boasted to her brother that she is going to get powers, her mother although disproving of her decision as she is afraid of what the city will do to her head supported her regardless and said she can come back anytime, she also gave her a good luck charm which is shown to be always attached to her bag.
Sometime in Academy City she became close friends with Uiharu Kazari, she eventually enrolled into Sakugawa Middle School along with Uiharu and was classfied as Level 0. She also let down her hair and wore a white flower on the left side of her head. She is currently a 1st year student in class 1-D.
Although her true ability is as of yet unknown and unnamed, under the influence of the Level Upper she seem to have power over the wind.
During the Poltergeist arc, she was armed with a Baseball Bat, and although it is unknown how well she fares with it, she proved instrumental in Therestina's defeat by destroying the capacity down.
She also is very athletic, being capable of running for a noticeably longer time than most students during her extra classes after the Level Upper incident, and was capable of quickly reaching the top floor of the large building that housed the Child Errors from the very bottom floor.
- In the manga she states that her nose is sensitive to money, she backs this up by showing Mikoto four bank cards she already obtained.
- She displays impressive skill in sewing.
- She and Uiharu Kazari both have cameos in both openings of the first Toaru Majutsu no Index anime, although with shorter skirts.
- It is speculated that Ruiko has a crush on Uiharu Kazari, although there is no solid evidence of this.