Saten Ruiko

is a character in the Toaru Kagaku no Railgun side stories. She is voiced by Kanae Ito. She is a Level 0 Academy City student and is a classmate and close friend of Uiharu Kazari.

Background
She was born outside Academy City and when she was younger she decided that she wanted to go to Academy City to learm, she even boasted to his 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.

Personality
She has an outgoing and friendly personality but is a little shameless as she sometimes flips Uiharu'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 abilities oneself at a time.

Like her friend Uiharu, she also has a deep sense of friendship, she was instrumental in helping Uiharu and Kuroko make amends and made Misaka realize that she has friends who she can count on.

The Level Upper Incidents
Unlike the manga, Saten has a much more prominent role in the anime series, she meets Misaka earlier and on the first episode she does her best to aid Misaka and the others despite having no abilities at all which impresses Misaka, she also gains the affection of Juufuku Miho a Level Upper user after she said as a passing remark that she liked her eyebrows during her visit to the School Garden in which she was attacked by her for wearing a Tokiwadai uniform.

Later she becomes envious by the fact that everyone of her friends has some sort of ability and becomes curious about the Level Upper, after obtaining it she becomes alienated by Misaka's words that levels and abilities are not important since to Saten having abilities is the reason why she went to Academy City, she finally uses the Level Upper after being caught helpless in the a battle between Kuroko and another Level Upper user where Kuroko obtained injuries. She invites three of her classmates to use the Level Upper, and Saten seem to display powers over the wind, however they were all soon struck by the side-effect of using the Level Upper, becoming comatose, she later goes back to her dorm and calls Uiharu that she has Level Upper and have used it along with her friends, blaming herself for what had happened, Uiharu tearfully says to Saten that everything is going to be alright and that she will be there to wake Saten up, she goes on to say Saten will always be Saten to her regardless of her abilities. This makes Saten feel better but when Uiharu arrived at her dormitory Saten has already become unconcious, she is later taken to the hospital by Uiharu.

After the defeat of Kiyama Harumi and AIM Burst creature she wakes up from her coma and is greeted by Uiharu on the rooftop of the hospital, Saten apologizes to Uiharu and realized that she almost lost something much more dear to her than abilities, she then proceeded to lift Uiharu's skirt once more.

Since she was a user of the Level Upper she has to take supplentary lessons at a certain school, there she meets there teacher, Tsukuyomi Komoe who teaches them the importance of having a Personal Reality for ability development, there she also once again meet with Juufuku Miho who shows a noticeable amount of affection for her. During running laps, Saten pushes herself to keep on running, there Elder Sister argues with Yomikawa Aiho stating that this just simply punishment for using Level Upper, Yomikawa rebuffs her stating that this is training to surpass one's limits, citing Saten and another runner as examples, she says to them that the development of abilities is akin in surpassing one's own limits. After going inside because of rain Saten confronts Elder Sister on her views on why this is like punishment and says that it is only natural for them to be punished becaused they were cheating (using Level Upper) in achieving abilities, which her friends agree on.

Later after taking in what Komoe says about achieving one's own Personal Reality and surpassing one's own limit, they are tested on how far their abilities have gone, Juufuku Miho having having witness Saten's confrontation with Elder Sister decides to follow her example and live strongly like her from now on and although Saten remains a Level 0 she is determined to keep on trying.

The POLTERGEIST Incidents
During the POLTERGEIST Incidents that are occuring around the city she befriends Uiharu's new friend Haruee Erii and helps both Uiharu and Haruee in fixing their yukata for an upcoming evening festival in the evening, during the festival Saten escapes unharmed during another POLTERGEIST-related earthquake.

Later when Kuroko and Uiharu came to a disagreement on Haruee's involvement in the POLTERGEIST Incidents, Saten is often seen trying to calm down the situation.

After discovering Telestina's true identity, she forces both and Uiharu and Kuroko to apologize to each other after treating each badly the past few days, Saten also chastises Misaka for not telling anyone where she went off to and reminds her that she is not alone, during the preparations in confronting Telestina Saten equips herself with a metal baseball bat.

She joins Uiharu in guiding Kiyama Harumi in finding the Child Errors that were kidnapped by Telestina, when they arrive at the location Telestina set-up a trap though she is unaffected by Telestina's Capacity Down because she is a Level 0, she later interprets Uiharu's queries on Telestina about the location of the sound system that controlled the Capacity Down, and later tells Telestina over the sound system to not to hurt her friends and then proceeded to destroy it with her baseball bat allowing Misaka to defeat Telestina.

She is last seen with Uiharu, Misaka and Kuroko being late for the special event held by Haruee Erii for Kiyama Harumi

SISTERS Arc (Toaru Kagaku no Railgun manga only)
Having heard of rumors of someone dropping bank cards, Saten uses her "nose" to find them and invites Misaka to join her. She later gives Misaka her share of bank cards and leaves afterwards stating that she would like to bring Uiharu next time.

Ability
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.

Trivia

 * In the manga she states that her nose is sensitive to money, she backs this up by showing Misaka four bank cards she already obtained.
 * She displays impressive skill in sowing.
 * She and Uiharu Kazari both have cameos in both openings of the Toaru Majutsu no Index anime, although with shorter skirts.