Name: Mikoto
Surname: Misaka
Age: 14
Level: 5
Known as: Railgun, Electromaster, Biribiri (by Touma), Onee-sama (by Kuroko)
Seiyuu: Satou Rina
Power: Electromagntism & Electricity
School: Tokiwadai Academy
She Likes: Gekota, Romance, Manga
She Dislikes: who can't overcome his limits

Mikoto is a Level 5 esper and she's considered the n.3 of Gakuen Toushi.
She has the ability to manipulate electromagnetism and electricity, and from them, the nickname she's known: Railgun.

Mikoto is tsundere~
She's proud and stubborn, the kind of person that can't live her life without doing something for who needs a hand. Usually, she wals on the street of the city to find someone to save or someone to kick, because she's easy to use her own power to let justice prevail.
But Mikoto can't follow the rules, she's easy to break them, and this is the reason why she's not part of Judgement, like Shirai Kuroko, her room-mate and friend. Also, Mikoto gets easily bothered of the things she does, and after an arc of time, she stops to do them, even things that a moment ago she liked a lot. She has a proper conception of justice and how the life of an esper could be, but since she wants to appear cold and arrogant to the others, many times she pretends to be very different from the real himself.

Mikoto is romantic and she likes cute things (like Gekota's gadgets), also she's an otaku and she loves to read manga, but she doesn't wants that the others know these sides of her, that she considers personal and partof a private life that she doesn't want to share with anyone. The reason is that Mikoto's life is difficult. Since her childhood, she was the target od scientists that tried to study her power using her dna in order to create copies of her. Mikoto's clones, that she calls "sisters", are the result of Mikoto's kind intention to help who suffers, donating her dna for a good cause, that scientists transformed in a killing game to create the first Level 5.

The plan to create it consisted in making stronger Accelerator, the n.1 of Gakuen Toushi, and in order to do it, he needed to kill about 10.000 Mikoto's clones, becoming more powerful day by day. It's thanks to Mikoto's determination and Touma's intervent if Accelerator was stopped, and the remained sisters were saved. Mikoto loves them and she desires to see them happy, like she wants to be.
After that, Accelerator changed his personality a lot, and meeting another, new Mikoto's clone called Last Order, he starts to spend his life protecting her and the other sisters. Mikoto doesn't know nothing about Accelerator changement, and for a long period she continues to believe that he's always the same person of the past, that can't understand how life is important, even the one of a clone.
But Mikoto's life isn't only that, because she's in love with a person that changed her destiny and the one of her sisters: Kamijou Touma. She's tsundere and she has strange ways to show him some her interests about his affair, but he's not interested in her, and after 22 novels and 3 of the New Testament, Ican safely and happily say that he considers Mikoto like all the others, because he likes to help who needs a hand like her, but he hasn't a love interest in anyone but Index.

Mikoto will always continue to follow Touma, but his feelings about her won't
change.

Another aspest of Mikoto's life is the one of her school activity. She's considered "The Ace of Tokiwadai Academy" and she's admired by all the girls of the school, that are her schoolmates but not friends. The only one that really love her because she share her life wih Mikoto is Shirai Kuroko, but Mikoto doesn't say nothing to her about her problems, the sisters and, also, her feelings for Touma. Kuroko understood that (it's obvious, knowing Mikoto and her tsundere attitude) but she doesn't know about other. Mikoto is lucky, because even if Kuroko feels like a friend that knows only "half" about her, she can't stop to be her friend and to stay by her side.
We have to say that Kuroko loves Mikoto in another way, not like a friend but like a lover, because she's totally homosexual. Also, Mikoto is friend of Uiharu Kazari and Saten Ruiko, students of a public middle school that is located in another district.

Their relation is better explained (only) in "To Aru Kagaku no Railgun", Mikoto's series~

Actually, Mikoto finds the existence of Misaka WORST in the journey in Hawaii, but she doesn't know about the one of Last Order, so, I'm soooooo curious to know her reaction when she'll see a super cute, little her in front of her eyes~