Rio Nakamura

Rio Nakamura is a student in Korosensei's Class 3-E of Kunugigaoka Junior High School.

Appearance
Rio has long, straight strawberry blond hair (blond in the anime and dark blond in the OVA) and grey eyes (blue in the anime).

Personality
Rio is a friendly, energetic girl and somewhat of a trickster. She's playful, has a bit of a dirty mind, and has been noted to be rather intelligent. She claims she was originally a serious person, something that would prove to be true when she disagreed with Nagisa's proposition to save Korosensei and continue to kill him.

Synopsis
Like the majority of her classmates, Rio debuted in the first chapter; however, she didn't originally get spotlighted until the first Finals Arc where she and Nagisa were the main rivals to Tomoya Seo in English. Before that, she was introduced during Chapter 18 where she was trying to peek in on Korosensei while he was bathing.

She gets another spotlight in Chapter 111, where she reveals her past as a gifted, but lonely elementary school student. She was the top student, but felt lonely and unsatisfied and wondered how would it be feel to be a normal student. Since then, she decided to "be stupid", by shirking off her studies and acting playfully. In the process, she completely forgot how to study and how take tests, prompting her fall into Class E. She expresses her gratitude to Korosensei for providing her with a place where she can both study and do "stupid things" along with her friends.

Rio contributes to Class 3-E's school festival in gathering the ingredients for their restaurant. However upon seeing Yuji Norita recognising Nagisa from the summer holidays, she quickly changes Nagisa's pants for her skirt and has him try to swindle money from the unsuspecting Yuji. Eventually Nagisa confesses that he is not a girl as Yuji had thought, Rio even covertly suggesting to Nagisa to "show it to him".

At the end of Chapter 142, when Nagisa proposes to find a way to save Korosensei instead of assassinating him, Rio is the first to speak against it. She cites the bond between assassin and target the the very reason why she wants to continue killing their teacher. Her disagreement eventually causes the class to split into either saving or killing Korosensei, prompting him to settle the dispute by having the two factions play a paintball match against each other. Rio joins the red (kill) team and acts as second-in-command to Karma Akabane.

When the strength of both sides have been cut in half, Rio heads to Ryoma's position and lie in wait until the blue team attacks to capture their flag. She reiterates her resolve to kill Korosensei, earning Terasaka's subtle praise. When the surviving blue team attack, Rio's group raced for the flag but but were ambushed from behind by Nagisa, thus eliminating her from the battle. She later watches Nagisa and Karma's brutal fight, which Nagisa eventually wins when Karma surrenders after being caught in a chokehold. Despite her earlier disagreement, Rio sees how both sides fought their very best and as such decides that Nagisa's side won fair and square. She even made up to Nagisa by playfully pinching him on the cheek.

Rio makes another major appearance during Valentines' Day, conspiring with Karma to teasing Kaede about her affections for Nagisa. The pair help Kaede build up her courage by taking her to spy on other couples throughout the mountain. Rio watched Kaede present her chocolate to Nagisa and afterwards confessed that she will not act on her own feelings for Nagisa for Kaede's sake.

Abilities
Marksmanship: Rio is ranked 3rd for marksmanship, girls' side, jointly with Kirara Hazama. They both scored 79/200 in a test in June.

English: Rio has a mastery over this subject and apparently the language itself and she's ranked 1st in the school for it.

Intelligence: Rio, despite her whimsical personality, is actually one of the smartest people in Class E, second to Karma. This stems from her past as a genius elementary school student and though she forgot how to study, she hasn't lost her own wit and guile.

Nagisa Shiota
Rio sits beside Nagisa enjoys messing with him and harassing him. She gets a kick out of playing on his androgynous appearance and according to the tankobon extra this is one of her hobbies. Despite that, the two are good friends and Nagisa doesn't pay much mind to her teasing.

In Chapter 116, Rio apologizes to Nagisa when she found out that the reason he kept his hair long was because of his mother's oppression, and says that she won't tease him about it anymore. However, the moment Yuji appeared, Rio breaks her promise and cross-dressed Nagisa.

It is implied in Chapter 159 that Rio has romantic feelings for Nagisa that she won't act on because she believes that what Kaede had done was "so gallant, [she] just can't steal it away from her."

Karma Akabane
For most of the series, Karma and Rio were not shown to be interacting much together and no romantic interest was ever shown. Their first known interaction was during the civil war when the two shared a common ground in opposing Nagisa's suggestion to save him. As the two most intelligent students of Class 3-E, the pair are of the same mind and it is even said that they can finish each other's thought. The two also share the pleasure of playfully teasing Nagisa.

Trivia

 * Her favorite subject is English while her worst is Civics.
 * Her hobbies are making jokes and sexually harassing Nagisa.
 * Her past club before joining the Class E was Amateur Radio Club.
 * She is the president of the Crossdressing Nagisa Appreciation Club.
 * Her favorite food is Pizza.
 * She wants to be a diplomat or an interpreter (presumably due to her English skills) in the future.
 * In the tankobon extras it was revealed that her current nickname is "Old Mannish Middle Schooler" while her past one was "Elementary School Genius."
 * She was paired with Sōsuke Sugaya in Nuru-Nuru Test of Courage in Chapter 74.
 * She was called "Gal English" during Class 3-E training using code names.
 * Her current hair color was revealed to be dyed as shown in a flashback in Chapter 111.
 * When she was in first grade, she got 100% on 6th grade tests.
 * Despite the way she acts, whenever a perverted situation happens, she's shown to be completely disgusted. However, she playfully notes that Taiga has a small penis while all the other girls were enraged at his flashing.
 * She says she hates looking at pictures of herself because she doesn't like her small eyes.
 * During the Civil War, she was eliminated along with Ryoma, Taisei and Takuya after Nagisa ambushed and shot all 4 of them.
 * She placed 11th overall during the first semester final exams.
 * In the tankobon extras, her statistics were listed as:
 * Physical strength: 3
 * Mobility: 3.5
 * Close-range assassination: 3.5
 * Long-range assassination: 3
 * Academic ability: 5
 * Characteristic skill: 4.5 (wasting talent)