Mugino Shizuri

Mugino Shizuri (麦野 沈利) is one of the Level 5 espers, ranking fourth after Misaka Mikoto, and is one of the antagonists in the Toaru Kagaku no Railgun manga.

She is the leader of ITEM, which is at odds with SCHOOL, another organization led by the second most powerful Level 5 Kakine Teitoku. She looks down upon lower-level espers and does not mind eliminating people who get in her way or who go against her, regardless of whether they are allies or enemies. Her overconfidence eventually results in her defeat against Level 0 drop-out Hamazura Shiage.

Background
Not much is known about Shizuri, though it is shown that when she was young, she was incredibly wealthy and even had a butler. She also seemed to have a snobbish look as a child. . Shiage noted that originally, from the girls of ITEM Mugino was the most beautiful endowed with both style and grace fitting for an ojou-sama

Personality
Mugino's appearance may suggest she's gentle and kind, but in reality she's a sadistic, battle-hungry fighter who looks down on all she deems weaker. She shows a compassionate face towards her teammates, although she would dispose them if they interfered in her way. Later in the series she develops a rather twisted interest in Hamazura after he defeated her, resembling a yandere crush in which she has marked him as her prey and hers alone.

Shiage accurately described her as an obsessive person, in his words Mugino is "The kind of person that can’t stand it when you can’t complete a video game without 100% accuracy" and "If you fuck up even slightly, you fly into a rage and won’t accept it even if you complete the game", he also adds that “''When someone like that fucks up even slightly, they find another goal in order to write it off. When you aren’t able to get 100% accuracy, you instead go for a high score and are satisfied with that''", in other words Mugino is someone who will completely obsess with victory once she sets herself a goal; coincidentally, Shiage will become Mugino's main objective and obsession once he defeats her for the first time.

Level Upper Arc

 * Main article: Level Upper Arc

She first appears during the Level Upper Arc, here, she is seen arguing with the rest of her team regarding going into public swimming pools, and is against the idea. When Frenda asks if they can go to a private swimming pool, she tells her that they can go when they have the time, much to Frenda's delight. They're conversation is later interrupted by the sound of the Level Upper treatment program being played all over the city, wondering what the sound is about.

The anime adaptation completely cuts out their conversation during this scene. It is instead replaced by a four second appearance in a cafe.

Sisters Arc

 * Main article: Sisters Arc

Prior to the events of the novel, she and her group are hired to stop Misaka Mikoto from destroying the facilities that are running experiments with the Misaka clones and Accelerator. During Mikoto's attack, they pinpoint two likely targets for the sabotage, here, she shows his intelligence as a leader by sending out Kinuhata Saiai to the inside of the facility to see if the attack is an inside job, and is later somewhat correct in her assumption as Nunotaba Shinobu is later caught by Saiai, and has Frenda guard it.

Both she and Rikou go to the other facility. When they figure out that Mikoto is attacking the facility Frenda is guarding, she and Rikou quickly bail her out, after being defeated by Mikoto, showing her immense destructive power to Mikoto in the process, forcing her to go on a defensive. With that, Shizuri has Rikou use Body Clear to track Mikoto during her defensive.

She later figure out that Mikoto is the one attacking the facility, and has Frenda and Rikou retreat, wanting to prove that she is the superior Level 5 herself. In their battle, she shows her superior physical condition to Mikoto, as the latter has been attacking facilities for several days without rest, forcing Mikoto to use Frenda's traps she left all over the facility as an advantage, making Shizuri enraged at Frenda for carelessly leaving her traps. Shizuri underestimates Mikoto's control on the traps and is later knocked-out by it. Shizuri later comes to, after Mikoto has finished destroying the facility and is about to retreat; even though she is nearly exhausted, Mikoto lures Shizuri into a platform with Frenda's traps once again, destroying it and making Shizuri fall. Mikoto tries to save her but Shizuri rejects her offer and instead falls, though she breaks her fall by using her Meltdowner.

Interested on the reason why Mikoto is fighting so hard, she apprehends one of the researchers retreating in the facility and finds out about the Level 6 Shift Program and decided to let her be, deciding that it would be best to let Mikoto suffer in the dark side of Academy City.

Later events in the novels
Volume 15 of the series is her and ITEM's first appearance in the main story line. She and her group was hired to stop SCHOOL's assassination on Director Oyafune Monaka. She kills Frenda for trying to defect to SCHOOL. ITEM fought SCHOOL once at Kirigaoka Girls' Academy, which resulted in Mugino's defeat by Kakine Teitoku, and half her coat being burnt, and half her face swelled up after being hit by Kakine.

During the events of Volume 15, she loses her left arm and part of her right eye to Hamazura Shiage. In Volume 19, they are replaced with masses of energy with the help of her own ability. When she reappears in Russia, she acquires a replacement arm and a monocle that snugly fits in her right eye socket. After losing her arm every encounter that she has with Shiage will leave Mugino more and more imbalanced, developing a huge obsession with getting rid of Shiage and by extent Rikou. By the end of volume 22 she finally decides to make peace with herself and with Shiage, finally returned to being the "old Mugino" who trusted her teammates and friends.

In, Shinyaku Toaru Majutsu no Index Light Novel Volume 01, Mugino has recovered from her previous injuries and rekindled relations with the rest of ITEM.

Abilities
Her ability is, which converts electrons into unstable destructive matter that is said to be in a state between particles and waves. She can use her ability to fire up to four beams at once, create a defensive shield that can melt/disintegrate steel, and supposedly her ability even grants her the ability to turn into an intangible energy, allowing her to phase through attacks. It is so powerful that she needs a limiter put on so that she doesn't end up hurting herself. She carries around silicon cards that can disperse her laser shots into multiple ones.

Unfortunately, her ability is highly unstable, as demonstrated when her anger towards Hamazura Shiage fueled her to use too much power and she blew off her own left arm from wrist to elbow.

Quotes

 * (Vol 19 and 22) "Why, did I become such a monster?"
 * (Vol 22, said to Shiage) “I killed Frenda. And made ITEM into a mess. Plus, more than once, I tried to take Takitsubou’s life. For someone like that, how do you plan to save me...”