Accidental Misnaming: Is rather annoyed that Touma keeps calling her "Biri-Biri" and kept telling him it's not her name. In the epilogue of the Sisters Arc, after she fails to give him her homemade cookies, she once again insists on him using her real name, to which he finally does indeed say it. Although the audience can't see, Kuroko mentioned that she had never seen that expression on her face before.
A-Cup Angst: It does not help that some of Academy City's younger girls are better endowed than she is. And it's hinted that Misuzu (who's well endowed herself, also to her daughter's chagrin) wants to rectify this fast (through food). Considering she's no more than fourteen, one would have to wonder why she's so bothered about it. This is again Played for Laughs during her first meeting with Misaka WORST.
The Ace: She's known as "The Ace of Tokiwadai", and she backs it up by being one of Academy City's most powerful espers.
Action Girl: She has slightly violent tendencies, and is ranked third among the Level 5 Espers.
Badass Adorable: She looks cute and innocent, which causes a lot of guys to hit on her. Unfortunately for them, she's also one of the strongest people in the city and has one of the most flexible powers in the entire story.
Batman Can Breathe in Space: In the Railgun S season finale, she and Kuroko were launched to the edge of the atmosphere without suits. While seemingly unaffected by the vacuum, they were visibly choking before they made it back to Earth.
Belligerent Sexual Tension: With Touma, to the point that she becomes the only other person (besides Heaven Canceler) who knows he has become amnesiac.
Berserk Button: There are only two things that make her angry enough nearby objects start sparking: threats to the Sisters, and Touma.
"If she let him get away, things would get very bad." "To put it in concrete terms, it was possible that she would end up with no scenes for three whole volumes." "Wait! Wait just a second!! This is my scene! If you’re going to do this, do it later!! Dammit, the guy-to-girl ratio here is completely out of balance. And is that group of huge breasts specifically targeted at me!? A-at this rate, I’ll be lost in the background…!! Did they create a forest to hide a leaf!?"
Breakout Character: She started as just another Girl of the Week, but proved so popular that she began to both appear more frequently, though still had little effect on the plot until World War III. She muscled her way into the story proper during the start of the New Testament novels and even got her own spinoff which has proven at least as popular as the main series.
Brought Down to Badass: During the Sisters arc, she's been going around trashing facilities for several days without eating or sleeping and is completely exhausted. After using the last of her energy to fight off Frenda, she's pitted into combat with Mugino and manages to use Frenda's explosives, a few passive effects of her electromaster powers and knowledge of the facility to bring Mugino down without enough power to use a single electric attack.
Character Development: Her primary flaw in the early series is pride; as one of the most powerful espers in the city, it's hard for her to even consider that there might be things she can't do and needs help with. As the series progresses, she evolves into a character more capable of accepting support from others and trusting people (especially Touma) to be able to solve problems on their own. This is sometimes described as "realizing Touma is the hero to her heroine."
Chronic Hero Syndrome: Despite Kuroko constantly warning her that since she is a civilian, she should leave the heroics to Judgment or Anti-Skill, she just can't help jumping in and helping. Ironically, Mikoto can't understand why Touma does the same thing.
Clingy Jealous Girl: Although it doesn't pop up too often, she's not too fond of how close Index is to Touma. And when he's seen hanging out with one of the Misaka sisters in episode 18 of season 2's A Certain Magical Index, she gets angry with him.
Cool Big Sis: Acts like this, especially in the Railgun series. Less so in the main series, since she hangs out a lot more with Touma who brings out her Tsundere side.
Cry Cute/Tears of Remorse/Tender Tears: Breaks down crying while she cradles a hideously injured Touma in her lap after brutally electrocuting him, realizing his point about the futility of trying to fight Accelerator to the death, noting how it will ultimately solve nothing.
Cunning Linguist: Besides Japanese, she knows other languages like English, French, and Russian. It comes in handy when communicating with the French-speaking Cendrillon.
Cuteness Proximity: Frogs, especially a mascot named "Gekota", so much so she thinks she sees a real-life version of it in the form of Heaven Canceller, of all people.
Death Seeker: Was planning on doing this, both in hopes that were she to lose to Accelerator on the first move, the calculations made for the experiment will be invalidated, as well as to atone for the suffering she put the Sisters through. Touma points out the flaws to her plan (even to the point of refusing to defend himself when Mikoto tried to zap him out of her way), that she won't be saved, and her death will not give the Sisters happiness, meaning in the end, no one will be saved.
Despair Event Horizon: During the Sisters arc, she constantly sacrifices sleep and fights constantly to the point of nearly passing out to stop the project. After seemingly wiping out every facility, more pop up and function in a way that actually benefits them if more shut down and then her last hope of using the Tree Diagram fails when she learns that it was destroyed. Upon learning this, she realizes she just can't stop the experiment and intends to go and commit suicide in a manner that will hopefully invalidate the premises the experiment was built on and end it.
Double Standard: Abuse, Female on Male: Frequently throws lightning at Touma whenever he does something to piss her off, and has tried hitting him with attacks that would very well have killed him if he didn't nullify them in time. Justified from her perspective because she thinks that he's just holding back and would just nullify them anyways. In the few times where he doesn't nullify them, she's shocked and realizes just how serious the situation has become.
Erotic Dream: Has one of Touma in the beginning of Season 2 Episode 17.
Even the Girls Want Her: Much to her chagrin. During the school festival episode multiple students try to give her gifts.
Failure Is the Only Option: All her attempts to stop Level 6 Shift are squashed by Academy City's administration before Touma lent a hand.
Fiery Redhead: Of a lighter shade, though she's certainly has the bad temper typical to this trope.
Flight: When she's over a body of water, she performs hydrolysis on the water particles so she can propel herself and fly.
Genre Savvy: She can read Kuroko like a book, and knows better than to take any gifts from her without making sure they're not laced with aphrodisiacs.
Glass Cannon: She´s one of the most powerful characters in the Toaruverse, but when Touma had his hand in hers to shut down her electric powers and had his other hand raised, she closed her eyes in fear and nearly started crying, as he himself lampshades that it´s hard to hit someone with a face like that.
Hair-Trigger Temper: Is rather quick to anger over the smallest of slights, and has a vengeful streak three-miles-wide towards those who personally wrong her (namely Touma earlier in the franchise, chronologicaly); that said, she WILL forgive (and even befriend) you after she has exacted vengeance by pounding you into the ground.
Hard Work Hardly Works: Subverted, as her quick ascent up Academy City's rankings is often held up as an example of how anyone can succeed with hard work, However, with the revelation that the scientists behind the Sisters experiment obtained her DNA map when she was at a lower level, and the much later revelation of the existence of the parameter list, this becomes a Double Subversion, since these mean that Mikoto had actually been pegged for greatness very early on in her development and was helped along the way much more than the average student.
The Hero: Shares this trope with Touma in her own series.
Heroic BSOD: After seeing one of her sisters die and being unable to do anything to stop it.
Hero with Bad Publicity: A plot point during the Shopping Mall Demonstration SS. Using a method of spreading rumors of a possible nuclear attack by her, every rioter in the area targeted her with rifles, axes, and every other weapon they could. This also counts as Mugging the Monster because if she wasn't The Fettered, she could have simply electrocuted them all and been done with it.
Hey, You!: She has yet to call Touma by his name. Save the PSP game intro and a small part in Volume 22 where she calls out to him.
High-Pressure Emotion: In more comedic scenes, she is prone to sudden puffs of steam to accompany her Luminescent Blushing to emphasize how vulnerable and embarrassed she is about feeling romantic-love towards Touma.
She makes fun of Touma for losing a 2000 yen bill to that evil vending machine, but in her first year she lost a 10000 yen bill to it, which is why she feels so justified in kicking and shocking it.
She gets mad at Touma for always calling her Biribiri instead of her name, but she never uses his name either. He's always 'you' or 'that guy.'
I Am Not Left-Handed: First, she can release a lot more electricity than she normally does, it's just that she typically holds back to avoid killing people. Second, she can use metal objects other than coins for her railgun attack, and the larger the object, the farther it can travel (since her range is due to the object vaporizing from air friction).
Jerk with a Heart of Gold: Short-tempered, vengeful and petty over the most childish-reasons, Mikoto is nevertheless kind-hearted and considerate to a fault, and unfailingly loyal to those who earn her respect/friendship.
Kindhearted Cat Lover: Mikoto has a huge soft-spot towards adorable baby animals, kittens in particular. To her disappointment, the ambient electricity generated by her sheer power causes discomfort in the poor little things, driving them away whenever she tries to play with them. This is a trait that the Sisters inherit from her.
Limp and Livid: Accompanied by furious shaking whenever she is about to go ballistic on Kuroko for her latest act of immature stupidity.
Little Miss Badass: Don't let her cute appearance fool you; this young lady is regarded as the third-most-dangerous person in Academy City for a very good reason.
Locked Out of the Loop: Is constantly left out of Touma's adventures. Even late into the New Testament series, she doesn't know about Imagine Breaker and thinks Touma can just negate things in general.
Love at First Punch: Mikoto became interested in Touma after he first blocked her electricity while she was zapping some delinquents.
New Transfer Student: In New Testament 5, she's planning on taking the entrance exam for Touma's school.
No Guy Wants to Be Chased: Well, Mikoto is a girl, but the chaser is female. In any case, Kuroko's clingy, perverted and creepy behavior clearly gets on Mikoto's nerves while she's friendly and generous to everyone else not named Touma. And unlike Touma, poor Kuroko isn't getting the tsundere treatment but rather the Vitriolic Best Buds treatment.
No Sell: An electric field around her prevents the Queen of Tokiwadai from tampering with her mind. Presumably, this also means that she's immune to other brainwashing and telepathic abilities. In chapter 61, Gensei Kihara finds a loophole. She's immune to a level 5's mind control, but the MISAKA network is not. So he uses Exterior to take control of them, fuses them to Mikoto, and then controls her indirectly through them.
Oblivious to Love: She's actually oblivious to her own love. It takes her until Volume 16 to realize that she likes Touma.
Offhand Backhand: In her fight with Touma during the Sports Festival (when she's in her angel form), she doesn't even look at him. She just casually sends ludicrously large bolts of electricity at him while trying to think of a way to destroy the Windowless Building. It doesn't work, because it's Touma, but she still treats him as a persistent fly rather than a serious threat.
Ojou: Everybody in Tokiwadai treats her as one. While she has the wealth and the status, she prefers to act like a tomboy with childish habits and is annoyed that everyone expects her to be a proper lady.
One-Man Army: She can take on entire Black-Ops battalions armed with automatic weapons with ease. Quite a few low-level mooks will surrender instantly when they realize who they're fighting.
Only Sane Man: She's the only one of the Level 5s that is considered publicly presentable and has become something of a mascot as a result despite her own quirks that keep her from being showcased too much. Accelerator and Kakine are antisocial murderers, Mugino appears normal but only until she gets angry, Misaki is paranoid and abuses her powers, Gunha is convinced he's a superhero, and the sixth Level 5 apparently never appears in public. Mikoto, by contrast, is just a tsundere tomboy with childish tastes. This is also only because the higher ups used mass media/rumors to create her ideal image and covered up Mikoto's various incidents.
Our Angels Are Different: In chapter 61 of the Railgun manga, she begins to Awaken to her angel form when fused with the MISAKA network. In the next chapter, while she is only two percent of the way to level 6, she calls down the strongest lightning strike ever recorded, and is specifically mentioned to be dozens of times more powerful than normal. She also learned how to teleport.
Out of Focus: In the Index series, where, despite often being billed as a main character, she hasn't been very plot relevant since the Sisters Arc.
Shock and Awe: The nature of her abilities. She's called "Railgun" for a reason.
Convection Schmonvection: Averted in Railgun Episode 12 where, against an opponent deploying a barrier that nullifies electric shock, Misaka uses the massive amounts of heat generated by her lightning to melt the thing.
Cursed with Awesome: Has a constant electrical field around her and cats won't go near her because of it.
Extra Ore Dinary: Can use her lightning abilities to control magnetism and therefore control metal. She can even use iron sand to make a WhipChainsaw!
Shown Their Work: Unlike most of the Technobabble in the series, Mikoto's railgun is actually surprisingly plausible. The effects shown fall into Artistic License a bit, but an MIT physics graduate found that the numbers we're given add up realistically.
Shorttank: And one who is quite embarrassed to show any sort of girlish behavior at that.
Stalker with a Crush: Although at that point the crush part was debatable, Mikoto did follow Touma quite excessively (including once chasing him around for a whole night).
Super Mode: In chapter 61 of the Railgun manga, Misaki's Exterior is used to force Mikoto to join with the MISAKA network in another attempt at a Level 6 Shift.
Ascend to a Higher Plane of Existence/Super Power Meltdown: Upon fully reaching Level 6, she would either ascend to Heaven, briefly opening a gate to the Territory of God, or implode like a white dwarf, destroying Academy City in the process. And since there are currently no more seats for angels in Heaven, it would be the latter.
Swiss Army Superpower: Normally, you'd consider generating electricity to be a fairly limited power. However, it's proven quite flexible.
She can of course zap you directly.
While based pretty solidly in physics, the author makes a point of noting that a resistor is only worth so much against electricity: That energy has to go somewhere, meaning it turns into heat instead.
She can manipulate current in order to create a railgun in the air and fire small objects with it, coins being her favorite. This is the source of her nickname.
Electric current running through her body makes her immune to mind reading, mind control and electric attacks.
Control of electricity equals control of electromagnetism apparently, so she can can control metal to make weapons and shields or walk on surfaces that have metal in them. This could be a wall, or it could just as easily be something that's magnetic but moving far too quickly for a normal person to stand on like a plane wing.
Being able to control electricity also makes her a supremely capable and quick hacker, even of military grade equipment with far more security than our own.
She never does it herself until forced to during an experiment to see if she could become a level 6, but states that through the use of bioelectricity you can form a network of a large number of minds, which is the center of at least two incidents she's involved in.
She can redirect attacks that are electron-based, even if they are not explicitly electrical, such as Meltdowner.
She can put out jamming frequencies, though apparently it's something of a brute force solution that jams all local frequencies.
If her muscles are paralyzed, she can manually control them by mimicking the normal functions of the nervous system.
Finally, she passively generates electricity at all times, which functions as a sort of personal radar. It's impossible to launch an attack from her blind spot because she doesn't have a blind spot.
Tomboy with a Girly Streak: She wears shorts under her skirt, and when allowed seems to prefer to do away with the skirt altogether. She's a bit violent and seems to enjoy a friendly fight. She's also a complete sucker for cute childish gekko items, and she likes large stuffed animals.
Trigger Happy: In the first episode of Railgun S she zaps a bunch of guys that had been chasing Saten (all at once) who were confronting Kuroko and Uiharu. She then reminds Kuroko and Uiharu the shop they want to go to will close soon then she says "By the way, who were those guys?"
Kuroko Couldn't you have asked that before you shocked them, Onee-sama?
Tsundere: Type A towards Touma. Kiyama, of all people, actually lampshaded it.
Unknown Rival: For Touma. Since his memories were destroyed he doesn't remember beating her the first time.
Unstoppable Rage: While destroying the facilities involved in Level 6 Shift Project (especially in the case of one she attacked after she found out Tree Diagram had been shot down, ruining her plan of hacking it to save her sisters).
Weirdness Censor: She already met several sorcerers and saw spells performed on a few occasions, but each time she either attributes it to esper powers or some other scientific explanation due to Academy City's abundance of espers. The one time someone tried explaining that's not how it works, they gave up before they even got to the point because Misaka asked a question while still trying to frame it from a scientific viewpoint.
When She Smiles: In Railgun S when the storyline starts to merge with Index's Sisters arc, after six episodes of running herself extremely ragged, not sleeping or eating, all to try to stop the Level 6 Shift project.
Wide-Eyed Idealist: At first, she had an idealistic view about Academy City. However, after the events of the Sister's Arc and experiencing first hand Academy City's dark side, she became more cynical, but avoided showing it in front of her friends.
"World of Cardboard" Speech: In New Testament Volume 6, when she explains why she's helping Touma to her opponent, the Valkyrie Brunhild Eiktobel.
You don't need a good reason to save a friend. If you want to save them, then save them. …I know someone who kept saying those stupid things even when he was driven to the brink of death, and he really did save over 10,000 people in the end. And that idiot that saved so many people is trying to save someone today like always. I know I can't stop him. No matter how much I don’t want him to do anything dangerous, seeing him off with a push to the back is the sign of a good woman!!
You Are Not Alone: When she properly reunites with Touma in New Testament Volume 2, she says this to him. Word of God states that she's now "entering the fight", meaning she's going to involve herself with Touma's adventures with the Magic Side. Sadly, she got dumped in the very end of New Testament Volume 3. Of course it didn't stop her from helping him in New Testament Volume 6.
Mikoto's underclassman in Tokiwadai Middle School, a Level 4 Esper, and member of Judgment. She has an obsessive crush on Mikoto, who she calls "Onee-sama" ("Sissy" in the dub), and is on the constant lookout for a chance to... get close to her (which Mikoto rarely allows, let alone appreciates).
Provides examples of:
Abhorrent Admirer: Mikoto views her as a friend and just a friend, so she gets pissed when Kuroko tries to be, well, Kuroko. If she's lucky, she gets electrocuted. If she's unlucky, she gets ignored in favor of Touma.
Badass Adorable/Little Miss Badass: Besides her power, she also knows martial arts like aikido and can easily take down grownup thugs. This extends to when she was in elementary school.
Barely-There Swimwear: Her outfit in Railgun Episode 13 shocked everyone by how ridiculously small it was.
Batman Can Breathe in Space: In the Railgun S season finale, she and Mikoto were launched to the edge of the atmosphere without suits. While seemingly unaffected by the vacuum, they were visibly choking before they made it back to Earth.
Beauty Is Never Tarnished: Averted in that Kuroko's job involves going up against thugs with no qualms about hitting her full on, and whenever they do manage to land a punch the damage stays. During the climax of the Level Upper arc she's too injured to participate in the fight and is shown to be in pain when she moves. She also winds up in a wheelchair for a while after a particularly brutal fight with Awaki.
The Cavalry Arrives Late: Whenever she scolds Mikoto for interfering with Judgment business, Mikoto will retort that if she and her Judgment colleagues would show up to a crime scene on time for a change, she wouldn't have to.
A Day in the Limelight: The Remnant arc in the Index series (Volume 8 in the novels / Season 2 Episodes 6-7 in the anime).
Demoted to Extra: In the Index series. While she was never that prominent in the first place, Kuroko's role has been reduced to occasional cameos, and once went an entire 15 volumes between appearances.
The Determinator: Overlooked a lot, but her actions in the Tree Diagram Remnant arc more or less confirm her as one.
Fille Fatale: A bit too sexually aggressive for a thirteen-year-old girl for comfort...
Fiery Redhead: Though less violent tempered than most girls of this trope, Kuroko still has the melodramatic and passionate personality that's typical of it.
Forgets About Her Powers: Despite her often ingenious uses of her power, she sure gets punched in the face a lot for someone who can teleport instantly. Justified by the fact that teleportation relies in incredibly complex 11th-dimension calculations, which isn't an option when faced with situations requiring instinct and reflexes.
Friend to All Children: Kuroko shows a surprisingly kind and soft-hearted side towards small children; she is a strict yet attentive and loving big-sister to any child under her charge.
Handicapped Badass: She was confined to a wheelchair for a while. Then she teleports with the wheelchair and uses it as a weapon.
Hidden Depths: Just as Kuroko is lustful, possessive, immature and selfish, she is measure for measure soft-hearted, kind, considerate and selfless. Never judge a book by its present cover.
Hypocritical Humor: After Kiyama started undressing in a cafe, Kuroko tries to stop her. When Kiyama explains that there are no men in the cafe, Kuroko retorts that there may be women with "twisted tastes" watching. Guess who she's talking about...
If It's You, It's Okay: Oddly enough, Kuroko doesn't view herself as a lesbian. When working together with Mikoto to take down an attacker holding hostages, she denies being into girls with complete seriousness.
Though she'd had her memories of Mikoto erased at the time, so its also possible Mikoto was her Closet Key.
Improbable Weapon User: Needles that she teleports into her opponent's clothes to pin them down or into them to cripple them. Also her wheelchair. When the situation is really serious, she'll use metal rods instead of needles.
I Want My Beloved to Be Happy: She does not seem to understand that "no-means-no" when it comes to her molesting behavior towards the decidedly-straight Mikoto, but when Mikoto is down she's worried enough that she'll even support Mikoto hanging out with Touma despite her usual jealousy. Nothing else seems to cheer her up, so if she has to hand her Onee-sama over to "that troglodyte" so be it.
Japanese Pronouns: Uses "watakushi", the more formal form of "watashi", as a first-person pronoun, which is linked to her being an Ojou.
Kawaiiko: She plays this image up for her benefit, but she can be aggressive and very sexually forward at the drop of a hat.
Leeroy Jenkins: As a Judgment trainee, she had a habit of charging at the bad guy without thinking. Konori scolded her for it and it nearly got everybody killed when she faced the bank robber who had the ability "Equal Speed". She occasionally reverts to this behavior.
Malicious Misnaming: She hates Touma, so she almost always refers to him as "The Ape" or "The Troglodyte".
Meaningful Name: Her name literally means "Black Girl White Well", highlighting the contrast between her cutesy facade and perverted personality. Mikoto even points this out in Railgin Episode 2 before beating her senseless.
Mikoto: I'm gonna fry you as black as your name!
Moment Killer: Amazingly, besides the usual examples, Kuroko is this to herself. Many is the occasion where she has a heartwarming moment with Mikoto... only to have her feelings get the better of her and abruptly launch herself at Mikoto, setting herself up for a beatdown. She also has a habit of ruining Mikoto's moments with Touma.
Ms. Fanservice: She's the primary one of the Railgun quartet. Mind you, due to her lack of development, this is just as often played for awkward laughs as it is occasionally played erotically straight.
Not Quite Flight: Can use her teleportation to move above ground level which becomes useful in the first episode of Railgun S when the bad guys try to flee in a helicopter. She can even do it from the upper atmosphere, allowing Mikoto and herself a safe trip back in Railgun S's finale.
She's Got Legs: Boy howdy! And the camera loves to remind us of that whenever she's in flight or arming the darts strapped to her thighs!
Single-Target Sexuality: She only expressed interest in both Mikoto and later her mother (who is almost the splitting image of her daughter, minus being more well-endowed). When her memory is wiped by the Queen she rejects the idea that she's a lesbian, which makes the situation she's in baffling for her since she can't help fixating over Mikoto.
Tele-Frag: By teleporting one object over another, she can displace matter occupying the old space. She once tore down a building by teleporting sheets of glass into the support pillars using this feature of her esper power. She also threatens to teleport her needles into people's bodies as a way to make them stand down.
Vocal Dissonance: There's a good reason Kuroko landed Satomi Arai her best supporting actress trophy, as it showcases her astoundingly flexible vocal range. Kuroko's voice is able to jump from sweet and girly, womanly and sultry to coarse and masculine at the drop of a hat.
Ascended Extra: While she has a major role in the Level Upper arc of the original manga, she's eventually shifted out of focus once that arc ends. In the anime, she's one of the lead characters, and is even inserted into scenes like Railgun Episode 1, where she was absent in the manga (she didn't even made her debut until the graviton bombings in Chapter 4). She comes back in the Daihaseisai arc in the manga, managing to wander into an area she really shouldn't and meeting Xochitl.
It's because she's a Level 0 that she’s immune to the paralyzing "Capacity Down" sound wave, allowing her to save her friends from Telestina's clutches in Railgun Episode 24.
Spends most of Daihaseisai as this, including, perhaps most importantly, lending Touma her charm. If she had never done that, he would never have been close enough to help out when Gensei attempted a Level 6 Shift on Mikoto.
In Railgun Episode 1, she saves a little boy from being kidnapped by a bank robber who has powers. Then, in the finale she smashes the Power Nullifier Telestina is using to incapacitate Mikoto, saving the day.
As of the premiere of Railgun S she may be heading for Chronic Hero Syndrome. As of the finale, she clearly is afflicted with it.
Seiza Squirm: Does this during the festival episode during a tea ceremony.
Shut Up, Hannibal!: Stops Telestina's gloating of humanity's supposed worthlessness by smashing the Capacity Down device paralyzing her esper friends with one mighty swing of her aluminum baseball bat.
Too Dumb to Live: She was borderline during the the Railgun SS. She followed Mikoto into what was clearly an off-limits area thinking it was a casino, where she nearly gets killed by Olive, and then there was the issue with Xochitl blackmailing her. She didn't piece together that those attacks were real until later and decided to investigate on her own, gets caught, and was about to be killed when Xochitl saved her at the last minute.
Troll: Not a major part of her, but her constant skirt flipping of Uiharu and teasing of everyone else qualifies her for it.
Kazari is Kuroko's friend, schoolmate at Sakugawa Middle School, and colleague in Judgment as a Level 1 esper, famous for wearing a headband made of flowers on her head (and sometimes a surgical mask in the manga). Usually shy and humble, her personality can quickly change to overly excited, especially if it concerns the life of the upper-class (particularly anything involving Tokiwadai).
Provides examples of:
A-Cup Angst: When Kuroko comments that her body is "underdeveloped", she gets upset.
Ascended Extra: Much like Saten, she's not really all that important outside the first story arc in the original manga. In the anime, her importance is significantly boosted.
Badass Bookworm: She’s not a warrior in the least, but her computer expertise makes her just as formidable, if not more so than, a dozen warriors in the right situations. She is in fact so good she can defeat even electrokinetic espers when it comes to hacking, including Mikoto.
In the SP volume, she jumped onto a moving truck from an overhead bridge, then deployed a parachute she was wearing as a drag brake in order to slow it down! The deceleration was so extreme that the metal handrails she was holding on to were yanked clean off the truck. Kuroko and Misaka, watching, state that she's in Judgment for a reason.
Cloudcuckoolander: She seems to edge into a state like this whenever she's in front of a computer.
Cuteness Proximity: Around Misuko's pet boa constrictor Ekaterina. Amusingly, the snake scared everybody else.
The Cutie: A small, cuddly and friendly breath of fresh air amongst her zanier friends.
Flowerbed In Her Hair: Whenever people ask about the flowers, she'll say she doesn't know what they are talking about. They are a headband of artificial flowers, and she wears it so often that she forgets about it.
Fluffy Tamer: Everyone else took one giant step back upon meeting Mitsuko's snake, Ekaterina. Uiharu stayed behind to coo over it.
Get a Hold of Yourself, Man!: In Railgun Episode 23, she suffers a Heroic BSOD when Telestina's true identity is revealed and she takes the children that were experimented on, causing her to break down crying until Kuroko slaps her across the face and asks her...
Ill Girl: In the manga, where she suffers from constant bouts of the flu.
Kawaiiko: Small, cuddly, vulnerable and prone to being the brunt of Saten's off-colored sense of humor and Kuroko's short temper.
Kill the Cutie: Narrowly averted in Volume 15, when she refused to tell Kakine where Last Order was even as she is being crushed to death. Accelerator comes in time before Kakine can deal the finishing blow. And as an illustration for New Testament Volume 1 shows, she has apparently gotten better since.
Mission Control: Often plays this role, usually with Kuroko on the other end.
Nice Girl: A warm hearted, caring and responsible young lady, with an occsaionally cheeky sense of good natured humor.
Non-Action Guy: As a trained member of Judgement, she should be an Action Girl with dangerous martial arts training. She...is not. Every time she goes out into the field, she gets hurt, so she stays at the office and plays support.
OOC Is Serious Business: Ruiko knows something is wrong when Uiharu doesn't react with embarassment to her skirt getting flipped up.
Playful Hacker: She makes hacking into high-security government databases without superpowers look like child's-play, and with a relaxed smile at that!!
Red Baron: Known as the "Goalkeeper" among hackers.
Salt the Earth: When she unknowingly caught Mikoto trying to hack into Academy City's main data centre and was unable to stop her, she decided to unleash Omega Secret on the database (or at least made it look like she did), which is an encryption program so complex it would take even Academy City's super computer 200 years to decrypt. In addition, each file is encrypted randomly, meaning each individual file will take another 200 years to decrypt. However, the encryption process to truly completely random, meaning not even Omega Secret itself knows how to decrypt it. So in one fell swoop, Uiharu made the database completely useless not only for Mikoto, but Academy City as well.
Utility Magic: Her power is useless in combat, but it's pretty handy for everyday life, such as keeping food warm, as well as advanced scientific purposes.
What Kind of Lame Power Is Heart, Anyway?: As the only named Level 1 of the series so far, it's no surprise her ability seems unimpressive. Her power is stabilizing the temperature of everything she touches — in other words, she's a human thermos.