|Birthday||February 13, 1998|
|Family||Aiza Takeshi (Brother)|
|Japanese Voice||Ai Kayano|
|English Voice||Stephanie Sheh|
Nagi is characterised by her blonde pigtails and golden brown eyes, often seen wearing her school uniform and raccoon dog hair baubles. She is described as very cute and pretty. In her early teens, she has yet to develop a woman's body and height. She establishes the cute little sister character in the story.
During her school performance, Nagi wore a formal green dress with a bow to tie it off in the back, and a black choker with a white flower around her neck. Her hair is worn in a high side ponytail.
Nagi is stubborn and somewhat childish. She is also cunning, and hard-headed.
Nagi maintains a realistic look in life and repeatedly testifies her hate for cliché. Because of her unerring piano skills, she is slightly arrogant and claims herself as "Angel of Kurumi Junior High". Nagi also appears to have a distaste for anyone who refers to their superiors without the appropriate honorific, as shown when Miike did not refer to Kousei Arima as his Sensei or Senpai, instead addressing him directly as "Arima".
Nagi is often seen to have a brother-complex, seeming to be completely fixated on her brother Takeshi. She idolizes her brother, and says she's "constantly chasing after him, but he is always ahead of her. " This complex has driven her to follow in his footsteps in order to get him to notice her and to also stop her brother's own fixation on Kousei.
Nagi set up a plan to sabotage Kousei, resulting in her being "knocked out," and Kousei having to bring her to Setos house. She then proceeds to ask Seto to teach her. Seto labels it as rude to her current instructor. Yet Seto asks her to play something. Nagi shows she is a brilliant player, and Seto agrees to teach her. She then shifts the position to Kousei, much to Kousei's dismay. Kousei corrects every aspect of Nagi's Playing, which makes Nagi upset and torts how he thinks he knows it all. In the later parts of the anime, Nagi warms up to Kousei, comforting and trying to make him smile while he was upset. Nagi holds deep respect for Kousei and admires him for his piano playing skills.
Nagi already has exceptional skills in piano before she became Kousei's apprentice. She is the prize winner of the Elena International Music Contest and Obtained the grand prize at the Matsuno Music Contest. When Seto-san asked her to demonstrate her skill, she easily performed Etude Op. 25 No. 5, the same piece Kousei played at the Maihou Competition.
During her lessons with Kousei, she blames her small hands for not being able to play in the right tempo or dynamic. Her skills improves drastically after being tutored by Kousei and can even keep up with his playing during her school festival performance.
Unlike most musicians in the story, Nagi doesn't perform for 'glory or perfection' but for obligation to become closer to her brother.
When she was younger, she saw her elder brother as some sort of hero. They often played together and had a close relationship, but Takeshi started to fix on Kousei Arima. Because of that, he started to practice hard and the strong bond between the two became thinner over the years. In order to be closer to her brother, Nagi starts to play the piano herself and enters a music Middle School.
- (To herself) "I hate incompetent people!"
- "How cliche."
- Nagi had a boyfriend named 'Kamiyama-senpai', but dumped him because she "can't stand the bookish, four-eyes type".
- Her hair clips are tanuki, a japanese raccoon dog.
- Nagi often makes references to herself using quotes from The Phantom of the Opera.
Takeshi Aiza: Nagi's older brother. He also plays the piano. She has a high opinion of her brother, and idolizes him, constantly trying to catch up to him.
Kousei Arima: Her tutor and friend. Though she is shown loathing him at first, she eventually finds out the knowledge her brother has of him is not completely true. She finds herself in him, realizing that Takeshi had been wrong all along. He "didn't have a heart of steel," and "his hands were warm when I touched them." She begins to warm up to him, as shown her thoughts and her defending him with fierce passion when Miike accuses her of her relationship with Kousei through jealousy. It is found that she eventually develops a crush on Kousei.
- ↑ Anime: Episode 18: Hearts Come Together
- ↑ Anime: Episode 17: Twilight
- ↑ Anime: Episode 16: Two of A Kind